Before getting too far with iOS development, it is really important to get a foundation on Apple's design pattern for developing on iOS. You might have used the Model View Controller (MVC) pattern with other technologies such as ASP.NET, but Apple implements this paradigm in a slightly different way. Apples core set of APIs for developing UIs for iOS applications is called UIKit. Xamarin applications can take full advantage of UIKit by directly using these APIs from C#. UIKit is heavily based on the MVC design pattern.
The MVC design pattern includes the following: