The table of contents feature lets you insert a widget with a list of headings (section titles) that reflects the structure of the document. The list stays up-to-date automatically as the user works on the document. Clicking a list item navigates the user to the corresponding document section..
You can also try the document outline feature that displays the list of sections (headings) of the document next to the editor.
Both table of contents and document outline are premium features available within the Productivity Pack. You can test them using the 30-day free trial.