diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/insert.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/insert.kt
index 5cb7742e16..8e93e6b0a4 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/insert.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/insert.kt
@@ -10,23 +10,137 @@ import org.jetbrains.kotlinx.dataframe.annotations.Interpretable
 import org.jetbrains.kotlinx.dataframe.annotations.Refine
 import org.jetbrains.kotlinx.dataframe.columns.ColumnAccessor
 import org.jetbrains.kotlinx.dataframe.columns.ColumnPath
+import org.jetbrains.kotlinx.dataframe.documentation.DocumentationUrls
+import org.jetbrains.kotlinx.dataframe.documentation.DslGrammarLink
+import org.jetbrains.kotlinx.dataframe.documentation.ExcludeFromSources
+import org.jetbrains.kotlinx.dataframe.documentation.Indent
+import org.jetbrains.kotlinx.dataframe.documentation.LineBreak
+import org.jetbrains.kotlinx.dataframe.documentation.SelectingColumns
 import org.jetbrains.kotlinx.dataframe.impl.api.insertImpl
 import org.jetbrains.kotlinx.dataframe.impl.columnName
 import org.jetbrains.kotlinx.dataframe.impl.removeAt
 import org.jetbrains.kotlinx.dataframe.util.DEPRECATED_ACCESS_API
+import org.jetbrains.kotlinx.dataframe.util.INSERT_AFTER_COL_PATH
+import org.jetbrains.kotlinx.dataframe.util.INSERT_AFTER_COL_PATH_REPLACE
 import kotlin.reflect.KProperty
 
 // region DataFrame
 
 // region insert
 
+/**
+ * This function does not immediately insert the new column but instead specify a column to insert and
+ * returns an [InsertClause],
+ * which serves as an intermediate step.
+ * The [InsertClause] object provides methods to insert a new column using:
+ * - [under][InsertClause.under] - inserts a new column under the specified column group.
+ * - [after][InsertClause.after] - inserts a new column after the specified column.
+ * - [at][InsertClause.at]- inserts a new column at the specified position.
+ *
+ * Each method returns a new [DataFrame] with the inserted column.
+ *
+ * Check out [Grammar].
+ *
+ * @include [SelectingColumns.ColumnGroupsAndNestedColumnsMention]
+ *
+ * See [Selecting Columns][InsertSelectingOptions].
+ *
+ * For more information: {@include [DocumentationUrls.Insert]}
+ *
+ * See also:
+ * - [move][DataFrame.move] - move columns to a new position within the [DataFrame].
+ * - [add][DataFrame.add] - add new columns to the [DataFrame]
+ * (without specifying a position, to the end of the [DataFrame]).
+ */
+internal interface InsertDocs {
+
+    /**
+     * {@comment Version of [SelectingColumns] with correctly filled in examples}
+     * @include [SelectingColumns] {@include [SetInsertOperationArg]}
+     */
+    interface InsertSelectingOptions
+
+    /**
+     * ## Insert Operation Grammar
+     * {@include [LineBreak]}
+     * {@include [DslGrammarLink]}
+     * {@include [LineBreak]}
+     *
+     * [**`insert`**][insert]**`(`**`column: `[`DataColumn`][DataColumn]**`)`**` /`
+     *
+     * [**`insert`**][insert]**`(`**`name: `[`String`][String]**`, `**`infer: `[`Infer`][Infer]**`) { `**`rowExpression: `[`RowExpression`][RowExpression]**`  }`**
+     *
+     * {@include [Indent]}
+     * __`.`__[**`under`**][InsertClause.under]**`  {  `**`column: `[`ColumnSelector`][ColumnSelector]**` }`**
+     *
+     * {@include [Indent]}
+     * `| `__`.`__[**`under`**][InsertClause.under]**`(`**` columnPath: `[`ColumnPath`][ColumnPath]**`)`**
+     *
+     * {@include [Indent]}
+     * `| `__`.`__[**`after`**][InsertClause.after]**`  {  `**`column: `[`ColumnSelector`][ColumnSelector]**` }`**
+     *
+     * {@include [Indent]}
+     * `| `__`.`__[**`at`**][InsertClause.at]**`(`**`position: `[`Int`][Int]**`)`**
+     */
+    interface Grammar
+}
+
+/** {@set [SelectingColumns.OPERATION] [insert][insert]} */
+@ExcludeFromSources
+private interface SetInsertOperationArg
+
+/**
+ * Inserts the given [column] into this [DataFrame].
+ *
+ * {@include [InsertDocs]}
+ *
+ * ### Examples:
+ * ```kotlin
+ * // Insert a new column "age" under the column group with path ("info", "personal").
+ * df.insert(age).under(pathOf("info", "personal"))
+ *
+ * // Insert a new column "count" after the column "url".
+ * df.insert(count).after { url }
+ * ```
+ *
+ * @param [column] A single [DataColumn] to insert into the [DataFrame].
+ * @return An [InsertClause] for specifying the placement of the new column.
+ */
 public fun <T, C> DataFrame<T>.insert(column: DataColumn<C>): InsertClause<T> = InsertClause(this, column)
 
+/**
+ * Creates a new column using the provided [expression][AddExpression] and inserts it into this [DataFrame].
+ *
+ * {@include [AddExpressionDocs]}
+ *
+ * {@include [InsertDocs]}
+ *
+ * ## Examples
+ *
+ * ```kotlin
+ * // Insert a new column "sum" that contains the sum of values from the "firstValue"
+ * // and "secondValue" columns for each row after the "firstValue" column.
+ * val dfWithSum = df.insert("sum") { firstValue + secondValue }.after { firstValue }
+ *
+ * // Insert a new "fibonacci" column with the Fibonacci sequence under a "math" column group:
+ * // for the first two rows, the value is 1;
+ * // for subsequent rows, it's the sum of the two previous Fibonacci values.
+ * val dfWithFibonacci = df.insert("fibonacci") {
+ *     if (index() < 2) 1
+ *     else prev()!!.newValue<Int>() + prev()!!.prev()!!.newValue<Int>()
+ * }.under("math")
+ * ```
+ *
+ * @param [name] The name of the new column to be created and inserted.
+ * @param [infer] Controls how values are inferred when building the new column. Defaults to [Infer.Nulls].
+ * @param [expression] An [AddExpression] that computes the value for each row of the new column.
+ * @return An [InsertClause] for specifying the placement of the newly created column.
+ */
 @Interpretable("Insert1")
 public inline fun <T, reified R> DataFrame<T>.insert(
     name: String,
     infer: Infer = Infer.Nulls,
-    noinline expression: RowExpression<T, R>,
+    noinline expression: AddExpression<T, R>,
 ): InsertClause<T> = insert(mapToColumn(name, infer, expression))
 
 @Deprecated(DEPRECATED_ACCESS_API)
@@ -34,7 +148,7 @@ public inline fun <T, reified R> DataFrame<T>.insert(
 public inline fun <T, reified R> DataFrame<T>.insert(
     column: ColumnAccessor<R>,
     infer: Infer = Infer.Nulls,
-    noinline expression: RowExpression<T, R>,
+    noinline expression: AddExpression<T, R>,
 ): InsertClause<T> = insert(column.name(), infer, expression)
 
 @Deprecated(DEPRECATED_ACCESS_API)
@@ -42,21 +156,84 @@ public inline fun <T, reified R> DataFrame<T>.insert(
 public inline fun <T, reified R> DataFrame<T>.insert(
     column: KProperty<R>,
     infer: Infer = Infer.Nulls,
-    noinline expression: RowExpression<T, R>,
+    noinline expression: AddExpression<T, R>,
 ): InsertClause<T> = insert(column.columnName, infer, expression)
 
 // endregion
 
+/**
+ * An intermediate class used in the [insert] operation.
+ *
+ * This class itself does not perform any insertions — it is a transitional step
+ * before specifying how to insert the selected columns.
+ * It must be followed by one of the inserting methods
+ * to produce a new [DataFrame] with an inserted column.
+ *
+ * Use the following methods to perform the insertion:
+ * - [under][InsertClause.under] - inserts a new column under the specified column group.
+ * - [after][InsertClause.after] - inserts a new column after the specified column.
+ * - [at][InsertClause.at]- inserts a new column at the specified position.
+ *
+ * See [Grammar][InsertDocs.Grammar] for more details.
+ */
 public class InsertClause<T>(internal val df: DataFrame<T>, internal val column: AnyCol) {
     override fun toString(): String = "InsertClause(df=$df, column=$column)"
 }
 
 // region under
 
+/**
+ * Inserts the new column previously specified with [insert] under
+ * the selected [column group][column].
+ *
+ * Works only with existing column groups.
+ * To insert into a new column group, use the overloads:
+ * `under(path: ColumnPath)` or `under(column: String)`.
+ * [Should be fixed](https://github.com/Kotlin/dataframe/issues/1411).
+ *
+ * For more information: {@include [DocumentationUrls.Insert]}
+ *
+ * See [Grammar][InsertDocs.Grammar] for more details.
+ *
+ * See [SelectingColumns.Dsl].
+ *
+ * ### Examples
+ * ```kotlin
+ * // Insert a new column "age" under the column group with path ("info", "personal")
+ * df.insert(age).under { info.personal }
+ *
+ * // Insert a new column "sum" under the only top-level column group
+ * val dfWithSum = df.insert("sum") { a + b }.under { colGroups().single() }
+ * ```
+ *
+ * @param column The [ColumnSelector] used to choose an existing column group in this [DataFrame]
+ * under which the new column will be inserted.
+ * @return A new [DataFrame] with the inserted column placed under the selected group.
+ */
 @Refine
 @Interpretable("Under0")
 public fun <T> InsertClause<T>.under(column: ColumnSelector<T, *>): DataFrame<T> = under(df.getColumnPath(column))
 
+/**
+ * Inserts the new column previously specified with [insert] under
+ * the column group defined by the given [columnPath].
+ *
+ * {@include [org.jetbrains.kotlinx.dataframe.documentation.ColumnPathCreation]}
+ *
+ * See [Grammar][InsertDocs.Grammar] for more details.
+ *
+ * For more information: {@include [DocumentationUrls.Insert]}
+ *
+ * ### Example
+ * ```kotlin
+ * // Insert a new column "age" under the column group with path ("info", "personal")
+ * df.insert(age).under(pathOf("info", "personal"))
+ * ```
+ *
+ * @param [columnPath] The [ColumnPath] specifying the path to a column group in this [DataFrame]
+ * under which the new column will be inserted.
+ * @return A new [DataFrame] with the inserted column placed under the specified column group.
+ */
 @Refine
 @Interpretable("Under1")
 public fun <T> InsertClause<T>.under(columnPath: ColumnPath): DataFrame<T> =
@@ -70,6 +247,26 @@ public fun <T> InsertClause<T>.under(column: ColumnAccessor<*>): DataFrame<T> =
 @AccessApiOverload
 public fun <T> InsertClause<T>.under(column: KProperty<*>): DataFrame<T> = under(column.columnName)
 
+/**
+ * Inserts the new column previously specified with [insert] under
+ * the given column group by its [name][column].
+ *
+ * If the column group with the provided [name][column] does not exist, it will be created automatically.
+ *
+ * For more information: {@include [DocumentationUrls.Insert]}
+ *
+ * See [Grammar][InsertDocs.Grammar] for more details.
+ *
+ * ### Example
+ * ```kotlin
+ * // Insert a new column "age" under the "info" column group.
+ * df.insert(age).under("info")
+ * ```
+ *
+ * @param [column] The [name][String] of the column group in this [DataFrame].
+ * If the group does not exist, it will be created.
+ * @return A new [DataFrame] with the inserted column placed under the specified column group.
+ */
 @Refine
 @Interpretable("Under4")
 public fun <T> InsertClause<T>.under(column: String): DataFrame<T> = under(pathOf(column))
@@ -78,29 +275,98 @@ public fun <T> InsertClause<T>.under(column: String): DataFrame<T> = under(pathO
 
 // region after
 
+/**
+ * Inserts the new column previously specified with [insert]
+ * at the position immediately after the selected [column] (on the same level).
+ *
+ * For more information: {@include [DocumentationUrls.Insert]}
+ *
+ * See [Grammar][InsertDocs.Grammar] for more details.
+ *
+ * See also: [SelectingColumns.Dsl].
+ *
+ * ### Examples:
+ * ```kotlin
+ * // Insert a new column "age" after the "name" column
+ * df.insert(age).after { name }
+ *
+ * // Insert a new column "sum" after the nested "min" column (inside the "stats" column group)
+ * val dfWithSum = df.insert("sum") { a + b }.after { stats.min }
+ * ```
+ *
+ * @param [column] The [ColumnSelector] used to choose an existing column in this [DataFrame],
+ * after which the new column will be inserted.
+ * @return A new [DataFrame] with the inserted column placed after the selected column.
+ */
 @Refine
 @Interpretable("InsertAfter0")
-public fun <T> InsertClause<T>.after(column: ColumnSelector<T, *>): DataFrame<T> = after(df.getColumnPath(column))
+public fun <T> InsertClause<T>.after(column: ColumnSelector<T, *>): DataFrame<T> = afterImpl(df.getColumnPath(column))
 
+/**
+ * Inserts the new column previously specified with [insert]
+ * at the position immediately after the column with the given [name][column].
+ *
+ * For more information: {@include [DocumentationUrls.Insert]}
+ *
+ * See [Grammar][InsertDocs.Grammar] for more details.
+ *
+ * See also: [SelectingColumns.ColumnNames].
+ *
+ * ### Example
+ * ```kotlin
+ * // Insert a new column "age" after the "name" column
+ * df.insert(age).after("name")
+ * ```
+ *
+ * @param [column] The [String] name of the column in this [DataFrame]
+ * after which the new column will be inserted.
+ * @return A new [DataFrame] with the inserted column placed after the specified column.
+ */
 public fun <T> InsertClause<T>.after(column: String): DataFrame<T> = df.add(this.column).move(this.column).after(column)
 
 @Deprecated(DEPRECATED_ACCESS_API)
 @AccessApiOverload
-public fun <T> InsertClause<T>.after(column: ColumnAccessor<*>): DataFrame<T> = after(column.path())
+public fun <T> InsertClause<T>.after(column: ColumnAccessor<*>): DataFrame<T> = afterImpl(column.path())
 
 @Deprecated(DEPRECATED_ACCESS_API)
 @AccessApiOverload
 public fun <T> InsertClause<T>.after(column: KProperty<*>): DataFrame<T> = after(column.columnName)
 
+@Deprecated(INSERT_AFTER_COL_PATH, ReplaceWith(INSERT_AFTER_COL_PATH_REPLACE), DeprecationLevel.ERROR)
 public fun <T> InsertClause<T>.after(columnPath: ColumnPath): DataFrame<T> {
     val dstPath = ColumnPath(columnPath.removeAt(columnPath.size - 1) + column.name())
     return df.insertImpl(dstPath, column).move { dstPath }.after { columnPath }
 }
 
+internal fun <T> InsertClause<T>.afterImpl(columnPath: ColumnPath): DataFrame<T> {
+    val dstPath = ColumnPath(columnPath.removeAt(columnPath.size - 1) + column.name())
+    return df.insertImpl(dstPath, column).move { dstPath }.after { columnPath }
+}
+
 // endregion
 
 // region at
 
+/**
+ * Inserts the new column previously specified with [insert]
+ * at the given [position] in the [DataFrame].
+ *
+ * The new column will be placed at the specified index, shifting existing columns to the right.
+ *
+ * For more information: {@include [DocumentationUrls.Insert]}
+ *
+ * See [Grammar][InsertDocs.Grammar] for more details.
+ *
+ * ### Example
+ * ```kotlin
+ * // Insert a new column "age" at index 3
+ * df.insert(age).at(3)
+ * ```
+ *
+ * @param [position] The [Int] index where the new column should be inserted.
+ *                 Columns currently at this index and after will be shifted right.
+ * @return A new [DataFrame] with the inserted column placed at the specified position.
+ */
 @Refine
 @Interpretable("InsertAt")
 public fun <T> InsertClause<T>.at(position: Int): DataFrame<T> = df.add(column).move(column).to(position)
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/documentation/DocumentationUrls.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/documentation/DocumentationUrls.kt
index 780da6c9fb..e6a3882281 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/documentation/DocumentationUrls.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/documentation/DocumentationUrls.kt
@@ -135,6 +135,9 @@ internal interface DocumentationUrls {
     /** [See `format` on the documentation website.]({@include [Url]}/format.html) */
     interface Format
 
+    /** [See `insert` on the documentation website.]({@include [Url]}/insert.html) */
+    interface Insert
+
     /** [See `rename` on the documentation website.]({@include [Url]}/rename.html) */
     interface Rename
 }
diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/util/deprecationMessages.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/util/deprecationMessages.kt
index 0c2833df57..19ad98d655 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/util/deprecationMessages.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/util/deprecationMessages.kt
@@ -139,6 +139,10 @@ internal const val COL_TYPE_INSTANT =
     "kotlinx.datetime.Instant is deprecated in favor of kotlin.time.Instant. Either migrate to kotlin.time.Instant and use ColType.StdlibInstant or use ColType.DeprecatedInstant. $MESSAGE_1_0 and migrated to kotlin.time.Instant in 1.1."
 internal const val COL_TYPE_INSTANT_REPLACE = "ColType.DeprecatedInstant"
 
+internal const val INSERT_AFTER_COL_PATH =
+    "This `after()` overload will be removed in favor of `after { }` with Column Selection DSL. $MESSAGE_1_0"
+internal const val INSERT_AFTER_COL_PATH_REPLACE = "this.after { columnPath }"
+
 // endregion
 
 // region WARNING in 1.0, ERROR in 1.1
diff --git a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/insert.kt b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/insert.kt
index 53875a86b5..c34b22727f 100644
--- a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/insert.kt
+++ b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/insert.kt
@@ -83,7 +83,7 @@ internal class InsertAfter0 : AbstractInterpreter<PluginDataFrameSchema>() {
 
     override fun Arguments.interpret(): PluginDataFrameSchema {
         return receiver.df.asDataFrame()
-            .insert(receiver.column.asDataColumn()).after(column.col.path)
+                    .insert(receiver.column.asDataColumn()).after { column.col.path }
             .toPluginDataFrameSchema()
     }
 }