my advice:
just kinda mess around with the program for awhile, and look through the help files.
pretty much all you need to know how to do to make amvs in any program is the following:
how to import footage & music
how to put footage & music on the timeline
how to cut footage on the timeline
how to move footage & music on the timeline
how to export
that's it, pretty short list.
everything else can be nice to know, but it isn't essential to be able to do things like zoom, fade in/out, overlay footage, speed up/slow down, etc...
probably the biggest pitfall for new amv-ers is trying to use divx/xvid footage
another big one is not syncing action and cuts
the guides are also helpful
the best part of this is that it's free, the only catch is that it takes time and effort
a lot of people on this site seem to have a "if you can't do it yourself then this isn't really the thing for you" mindset. Pour some sweat into it, and then ask for help if you need it