Add a Table of Contents - new Google Sites
Insert an automatically-generated table of contents that links to the headings you choose through page anchors in new Google Sites
Add a Table of Contents
Open the right-hand Insert panel
Use the Table of contents option
The table of contents appears on the page and you can move and resize as necessary
You can choose to display the table of contents links either indented by heading level or to have a flat table of contents.
You can choose to hide certain titles, headings and subheadings by using the hide/show icon that looks like an eye.
All titles, headings and sub-headings outside of the page header appear in the table of contents. Titles, headings and subheadings in the page header do not appear in the table of contents.
There are no options to change the formatting other than whether the links appear indented.