You're a noob? That's okay, man. Not a problem.
The gas tank is dented so that the cap just won't fit right? Yes, the simplest fix would be to get another tank. They're only about $25, if I remember right. You could try to pop out that dent, I suppose. But it might be hard to get it just right. Plus these tanks are not really all that high quality. You're liable to cause cracks. And that means leaks. But you got nothing to lose by trying, right?
When your chain comes in, you should probably think of yourself as starting at square one.
So why don't you have a look at this thread. It'll get you started.