Click on the "Pages" tab near the top of the right sidebar
Click on the "+" symbol near the bottom of the right sidebar
When you hover your mouse over the "+" symbol, you'll see another option. Clicking "New link" will create a link in your navigation menu to an external website. For the purpose of this tutorial, we are going to stick with creating an additional page.
A box will pop up asking to name the new page
Type in the title of the new page
Click the Done button
You will automatically be taken to the new page
To create a subpage (an additional page that is nested underneath a page in the site navigation), click on the three dot menu near the title of a page in the sidebar
In the menu, click on "Add subpage"
A box will pop up asking to name the new subpage
Type in the title of the new subpage
Click the Done button
You will automatically be taken to the new subpage
Click on the title of pages in the sidebar to move between them
Go here to learn about publishing the site