Is there a guided tour?

Yes. Click "Guide" at the bottom of the sidebar and choose the tour "Activity Studio: puzzle books" (it is marked "this page" while you are in Activity Studio). Start it while your maze book is open: it points at each part of the screen: Ready to publish, The book, The mazes, Mazes inside pictures, Your own pictures, Letters and names, Stars and ghosts, Loops, How the walls are drawn, Pages and solutions, Maze names, Cover and listing text, The real page, Every maze, New mazes, Export and publish and The difficulty curve, and ends with "A book worth buying". Steps about a part that is not on screen (for example Letters and names in a book of square mazes) are skipped.