Advise, please

I’m far from an expert in AS3, but I’m learning fast. I know a lot of stuff, and I’ve learned what I need to learn, and because of this I probably missed out on some of the more basic stuff. Anyway. I’m creating a game and it has many functions. Should I separate these into different classes? I know this is a really basic question, but I didn’t learn this, but learned many other things…

Say I have logging in and registering. Should I separate those into different classes? If so how do I define my own new class? Then to call it do I just have to import the class name?