Could someone expand and clarify the different logical instantiations of objects in actionscript? So far it seems there are 3 layers of instantiations, for lack of a better term.

The first one is declaring a variable/type.

Next is instantiating that variable with something solid in the code, like a method or function? Is this just a way to glue things together?

Then after that you instantiate it on the stage, is this something you have to do explicitly, or is it a side effect?

Is this "3 layer" concept the correct way of looking at it, kind of like the MVC for flash app logic?