Ebook included in the project explains the function of each class of the project.
It 'a chapter dedicated to the creation of a package iTunesConnect In-App Purchase
Some excerpts from pdf :
The app is made up of six classes, each with its own specific function: ViewController, that introduces the app to the device on which it has been installed, is the class from which all app features start (take a new photo, library photo selecting, purchase through In-App Purchase), and it has also got an iAd banner at the bottom part.
BabyViewController, from here you can buy through In-app Purchase the other 9 dinosaur puppies that complete the app. As expected, in this view the purchase “restore” is also managed. We have a UIScrollView showing all 9 puppies presented in the set PhotoController, the app heart, from here you can add the dinosaurs to the photo selected from the library or already taken. Once you have selected the kind of dinosaur, you can rotate, zoom and obviously move it in the scene. When you have chosen the position you like the most, we can save the whole. At the bottom part there is an iAd banner.
RiepilogoViewController, from here you can see the photo modified like it has been saved on the device, and we can share it on Facebook, Twitter, Flickr, Mail and Messages. Once you have finished this step, you have to go back to the main menu represented by ViewController class. IAPHelper & BabyDinosaurs, they manage In-App Purchase