I'm not sure what it's called exactly. But I want to make it so the previous one or two frames are drawn, or at least outlined, even when I'm not on them. So I can see where figures just were and can have an easier time making a smooth animation. I'm a complete beginner at this, but I know that Adobe Flash CS4 should be able to do that. Any help?

It's called an onionskin. There are three buttons underneath the timeline that look like squares - one is the onionskin outline and another is onionskin shadow. If you can't find them I can try to get a screenshot for you.

Edit: Since PC already has a picture of what they look like: