When you click on the second Toolbar icon, NAVIGATION, you get a slide-out with the current pages of your website.

Clicking on the Add a New Page button will add a blank page.  Be careful and don’t keep clicking on it if you don’t see the New Page.  

It is there at the bottom of all of the pages, so scroll down and you’ll see it, as in this image at the bottom.

Now you need to name your page.