At first, I find it is hard to use Windows Movie Maker. It is normal for the beginner actually. Therefore, down here I listed a link that can help you to understand and master more in WMM.
http://www.windowsmoviemakers.net/Tutorials/
youtube:
~video editing: http://www.youtube.com/watch?v=JZXK68NS7gU
~basic tutorial: http://www.youtube.com/watch?v=6DHFKVzG8Zw
