Adding subpages to the site will allow you to organize a large number of pages into a drop-down menu and also categorize them. For that, follow the instructions below.
Adding subpages in the pages list
Access the editor of the site and navigate to the list of all pages:
Choose a page which you'd like to make a subpage and click on the three dots here:
Choose Convert to subpage:
See that a page becomes a subpage:
Alternatively, click on Create subpage to add a brand new page to the site:
Important: note that these subpages will only be displayed in the pages menu (a list of pages you see in the editor). For the subpages to be visible to the site visitors, make sure you add them in the navigation menu.
Adding subpages in the navigation menu
1. Click on the menu settings:
2. Hover over the page which you want to make a subpage and click on the three dots:
Choose "Convert to subitem":
This is how it will look on the published site:
Check the article below for more info how you can customize the navigation menu: