If you received a book gift from a friend you activate it by clicking on the link in the email. this brings you to our website where you choose a password. Download the app and log in with your email and password, then search for the audiobook you want to listen to and save in your book shelf -> "Play book".
Keep in mind: If you have chosen to listen to a book you cannot change to a different book. It is possible to listen to a preview of the book if you click on the "Play"-symbol on the cover of the title.