Is there a guided tour?

Yes. Open a coloring book, click "Guide" at the bottom of the sidebar and start the Activity Studio tour (it is marked "this page"). In the studio it points at each part of the screen: Print check, The book, The designs, Color by number, Pages, Cover and listing text, AI drawings (only when AI drawings are among the kinds of design), A page from a photo, Color it in and Every design, and ends with tips for "A book worth buying".