Hi-I know what you mean about not having a clue how to use it-I am no expert but I just discovered the Movie Maker 4 days ago and I have made a 14 minute movie so far. I made it with pictures I scanned into my computer and music that I had downloaded. I don't know about getting movies from a video camera or other sources. (yet) I would suggest just start playing with it and seeing what it can do and how things work. Even if you don't have the pictures you want to make your movie with on your computer yet, you could just use any sample images or pictures you may have and get an idea of how to use it. Even the same picture over and over again would give you an idea of how the transitions and effects work. It is really pretty easy once you start using it. As far as getting the movie saved, that's where I am stuck, my computer won't let me save it to a CD or anywhere else. Hopefully you won't have the same problem.
Have fun with it!