Hi there,
you would build your navigation using custom links, the URL for each will point to an ID that will be used on your page e.g:
#about
Then on your page you need to assign that ID to the element you want it to jump to e.g:
<h2 id="about">About</h2>
Or if you are using GP Sections for example you can add that ID in the Sections settings.
If you want the page to smooth-scroll to that link when clicked you can do this:
https://docs.generatepress.com/article/smooth-scroll/
The smooth-scroll
class can be added to the CSS Class when creating your menu items. If you can’t see this field, when editing the menu, click the screen options tab at the top of the screen and Check the CSS Classes checkbox.