In fact, the sample screenshot has a “SCREENS” option that I dont have.
They must have taken those screen shots on a beta version of the software. I have Layout (which they may be considering changing to Screens) and Tabs (which shows as Navigation). If you click on Layout, there will be one called Tiles. That is what is showing in your screenshot.
I think those are old screenshots. Several things have changed with how the builder looks over the past couple of months.