In each page correspond one category of questions. To go to the next page of book you have to answer correct one question of the corresponding category. Something like the module Lesson but far more simple.
I went and had a go (great that guests don't have to log in ).
I was able to answer questions but didn't get any feedback as to whether my answers were right or wrong. Is this how it is supposed to work: as a formal test not a learning exercise?
In a better demo in each page there is a category of question which has question that refers to that page.
If you read the page and understand it you can answer the question and go to the next page.
Is something like the module lesson but more simple.
What if the Book module is already installed?
Yes, The book should be created in your course.
But we have version of Moodle - 2.4, installed the module Game from the page with this address - https://moodle.org/plugins/view.php?plugin=mod_game, version - 184.108.40.206 (2013090702), and all games work, but only this game (book with questions) does not give to add questions form categories. Vaybe I do something wrong, but I cann't see/ how to add questions to this game