In view mode, you'll see a simplified content diagram made up of horizontal lines on the right edge of the page. Each line corresponds to a page heading, and the line length indicates the heading's level. When you scroll the page, the line on the diagram that matches where your cursor is on the page lights up.
To view the page's table of contents:
Hover over the heading diagram on the right edge of the page and wait for the panel with a table of contents to appear.
Screenshot
To jump to the heading you need, select it in the table of contents.
To pin the table of contents, click .
To see or hide the table of contents, click the Table of contents button on the right side of the top panel.