Um... just experiment! Today was my first time using any manual settings with a digital camera, and boy is it NICE! The LCD screen obviously isn't exactly what your print looks like, but it's really close. So the nice thing is, you can take something like fireworks, moving water, sports, etc with a variety of shutter speeds and see instantly which direction you need to go to accomplish your goal. Even if you don't have a goal, you can see what the different settings do without a) wasting film and b) having to wait until the pictures are developed, and then try to remember what was what, etc!
I think your users' manual should have a good basic explanation of the shutter speed, aperture, etc concepts. Nothing that would make you or I a professional obviously, but at least gives you a place to start! Generally speaking, a slow shutter speed "blurs" action. So the really great pictures on the photography board of fireworks (or a good landscape picture of a waterfall) that show the whole motion of the firework were taken with a slower shutter speed.
For example this:
Vs this
The apterture (f-stop number) is how much light gets into your camera's lens. The only thing I know how to do with that is change the depth of field. A larger aperture will sort of blur the background and really focus on the subject, whereas a smaller one will give equal consideration to the foreground, background, etc.
Hmm.... anyone else better at photography that can clarify my jumbled mess?!
Hopefully your manual is well-written
Like I said before I went off on a tangent, my best advice is to take lots of pictures... you can always delete them!