A book is not typed in lesson by lesson. You give it the PDF, it is read for you, and you are shown the units, lessons, questions and pictures it found - and correct them - before anything reaches the library.
Open Library, then Browse, and stay on the list of series.
Import Book only appears there - a new book has to be filed in a series - and only for a full-access administrator.
Press Import Book.
Choose the Series, or Create a new series.
Creating one asks for its title and description here.
Give the book a Book code and an Order.
The code starts the name of everything the import makes (de1-book, de1-u0-l0 …), so keep it short. Order is where the book sits among the others in the series.
Press Choose PDF and pick the file.
Press Read the Book.
One AI call reads how the book is divided, and the import screen opens on what it found. Nothing is in the library yet.
Work through the import screen: the structure, the reading, the content, then the write.
Each step has its own "?", and its own article on this shelf.
The book arrives unpublished, so nobody reading in the app sees it while you tidy it up.
Pictures are taken out of the PDF for you. Only a diagram drawn as lines stays a placeholder, and the last screen lists those so you know which lessons to open in the Lesson Editor.
No Import Book button means AI is not switched on for your ministry. A button you cannot press means it is switched on but has no key yet - hold the pointer over it and it says which.