The pages section will allow the user to add different pages into their Google Site whilst manipulating how each page is managed. For example, you are able to make a specific page the homepage for the whole site, you can add sub-pages so there is the options for drop downs.
In the Pages section, it will show all of the pages which are currently created on your Google Site. To create a new page, you will need to click on the '+' icon at the bottom of the screen. You will be given the option to add a new page or a new link.
The new link option will allow you to create a link to a certain page on the site for quick access. The new page will allow you to create a new page where users can navigate to.
Once you have created your Page, you can start to add content to it which can be found in the Insert Tab.
If you are wanting to create a drop-down menu for a different number of pages, click on the three dots icon next to the page name and click on 'Add subpage'. This will then allow you to add a page onto an already existing page.