Beginner's Question: Where to initialize classes?

Your question is a bit open-ended and vague, but here is a general answer.

You initialize any object typically at the time of creating or instantiating it in the program. It can happen anywhere or any time depending on what the class is and what you are doing with it. You basically ignore the main file. It is just a startup file for the program. All your work is done in the class files you create - typically in the ViewController classes.

Your .h and .m files are only a blueprint or description of the class. Just having the .h and .m files in your project does not mean the class or object actually exists in the program. It only exists when you declare it as a variable of another object you are creating or when you assign it to a pointer in your program.

Code:

UIView *my_view =[UIView alloc]init]

Every time you create a new instance of the class you have to alloc init the new object. It does not have any connection to any other instance that you might have created before. Well, not every time. There are cases in which you only assign an object to a pointer but it does not get allocated, such as copying some string data.

Code:

NSString *string = [textField stringValue];

Objects in your Interface Builder .xib files get initialized automatically when the .xib file is loaded.

Sorry if I went into too much obvious detail. Your question was too general so I don't know exactly what you are unsure about or what you already know.