First, don't get discouraged. You will learn as you go along, but basics are not that difficult.
A tippet is part pf the leader. It is usually the last twenty or so inches at the tippet end--the fine end. I'd suggest to take it slowly, using, perhaps one good book which gives you a very adequate "course", so to speak, on fly fishing.
Most beginning fly fishermen want to learn how to dry fly fish. One of the best books I've ever come across is written by Art Lee. The name is "Fishing Dry Flies For Trout On Rivers and Streams". Once you get some basics learned, then you can concentrate on learning more about individual insects and their imitations.
If you do not want to go the book route, I suggest looking here:
Fly Anglers Online
Look at the menu to your left. There is a section that is titled "Fly Fishing Basics". Once you get to that page, again to your left in the menu is a section called "Fly Fishing 101". It is a good place to begin.
If you have specific questions we can help you with, feel free to ask.