That’s possible and quite easy to do, I hope. When you create a new setup, you’re greeted with a single empty playlist named My first playlist:
You can now fill this playlist with content by adding new Pages to it. If you want you can combine multiple types of content on a single page, like a video on the left and an image on the right side.
If you just want to create pages with a single item (image or video) in fullscreen, there’s an easier way. Click on the Switch to compact editor button. The interface switches and makes it easier to just add fullscreen assets:
On the right hand side you see all your assets and can use the search box to search in them. Filling your playlist is then as easy as drag-and-dropping assets from the right hand side into the empty box on the left. In the playlist you created on the left side you can reorder your items (using drag-and-drop again) or delete them.
If you decide you want to modify a page and add additional content to it, you can switch back the the detailed editor with the Switch to detailed editor button.
Let me know if that helps.