Choose Insert - Table of Contents and Index - Table of Contents, Index or Bibliography - Type tab (when Table of Objects 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 - Table of Contents and Index - Table of Contents, Index or Bibliography, 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 LibreOffice - PreferencesTools - Options - LibreOffice Writer - Formatting Aids, and then select the Enable cursor check box in the Protected Areas section.
Create index for
Select whether to create the index for the document or for the current chapter.
Create from the following objects
Select the object types that you want to include in a table of objects.