How to include illustration index inside table of contents?

I am doing final adjustments to my graduation thesis. My mentor had couple of remarks i need to change. First of all i have two custom illustration indexes, that come before “content” if you understand me. Table of contents should look like this: illustration index 1, illustration index 1, and then index from outline numbering from my paragraphs.

But i still can’t figure out how to do this? Any help would be much appreciated. Thanks :slight_smile:

Is your question about how to insert an illustration index or about how to format index or index title as in @RGB-es’s answer? (Answer through editing your question, not by using an answer)

The title of those illustration indexes use a particular paragraph style, such as “Figure Index Heading.” You can know which style is used by opening the style editor and then clicking on the index heading. Edit those styles and, in the “Outline & Numbering” tab, pick the desired outline level. Now, you just need to update your TOC and those indexes will be there.