Make a nav link

Open two tabs. First tab to directly edit your website. The second tab that is opened to the published page.

On the first tab, make headings or subheadings for the sections.

On the second tab, the published page, hover over a heading and click the link icon that appears to copy the link URL.

Edit the site and select the Pages section.

Click the + and create a link.

Name the link and paste in the link and select to open in the same page.  This only works in navigation links. Text links and buttons do not have the option to open in the same page.