The framework defines a specific set of rules for assembling high-level components. These rules define how objects should be assembled, how they should be connected and how they should be accessed. You also need to know why these rules work. To do this, you need to understand the following topics:
The importance of encapsulation.
How delegation is used to send a message.
Object access methods and delegation - how delegation is used to find an object's ID.
How object access methods allows objects within a component to communicate.
Dependencies between objects and how they are used within a component.
Once these topics are understood, you will see why a high level component such as a view is assembled as it is.