The following options are available when you select Table of Contents as the index type.
Choose Insert - Indexes and Tables - Indexes and Tables - Index/Table tab (when Table of Contents is the selected type)
Type and Title
Specify the type and title of the index.
Select the type of index that you want to insert. The options available on this tab depend on the index type that you select. If the cursor is in an index when you choose the Insert - Indexes and Tables - Indexes and Tables, you can then edit that index.
Enter a title for the selected index.
Protected against manual changes
Prevents the contents of the index from being changed. Manual changes that you make to an index are lost when the index is refreshed. If you want the cursor to scroll through a protected area, choose Tools - Options - LibreOffice Writer - Formatting Aids, and then select the Cursor in protected areas - Enabled check box.
Create index for
Select whether to create the index for the document or for the current chapter.
Enter the number of heading levels to include in the index.
Use this area to specify which information to include in an index.
Creates the index using outline levels, that is, paragraphs formatted with one of the predefined heading styles (Heading 1-10) are added to the index.
You can also assign the outline levels in the Outline & Numbering tab page of the Format - Paragraph dialog.
Includes the paragraph styles that you specify in the Assign Styles dialog as index entries. To select the paragraph styles that you want to include in the index, click the Assign Styles (...) button to the right of this box.
Opens the Assign Styles dialog, where you can select the paragraph styles to include in the index.
Includes the index entries that you inserted by choosing Insert - Indexes and Tables - Entry in the index.