The Model and Application Structure
In this part . . .
Now you begin to get down to the real work. You find out about Split View controllers and popovers (when building the iPad version of the storyboard file) and also add navigation to the application. You also add the application model, which provides both the data and the logic you need to create an application that delivers real value to the user. Finally, you finish the iPad and iPhone storyboard files so that you can see your basic application flow.