MVC structure

iOS uses a Model View Controller structure

The model contains your data, the view where it's displayed and the controller how the view and the data are displayed.

You can move from one view to another using Segues

In order to pass data from one view to the other we use app delegates and protocols
ViewDidLoad is called when your view loading is finished and loadView is called when loading starts.
And when you make a new project you see comments on these methods which clearly gives a tip when
you should use which function