if you have a camera with a light meter, the first thing you need to do is go to a drugstore, department store or camera store and put a new battery in the camera. the battery can be removed by unscrewing the 'plug" under the camera. look at the # on the battery and get the same one of the one tha "replaces it"
with the lenscap off, take the camera, put the shutter speed on something like 60 (dial ontop of the camera) point the lens at a bright light or the sun and move the aperature ring to both sides ( larger numbers and smaller numbers) .. you should see the needle inside the camera ( sometimes on the right sometimes on the left) or red/ green lights on the bottom of your viewer chaning color. if they don't, your light meter might not be working. if that is the case, you might need to go to your local yellow pages and see if you can find a repair guy to take the camera to. if the needle is mooving, and the led lights inside the eyepiece are changing colors, you are in business.
you want to adjust the shutter speed and the fstop to the needle is in the middle, or maybe a little towards the "+" or "-" depending on what you want to do. led lights, i think the 2 lights turn into 1?? not sure. play with the camera a little bit you'll see that the fstops shutter speeds and asa ( film speed ) are all interconnected...
as for the flash ..
the "sync" speed is either 60, 125 or 250, there might be an "X" next to the # or it might be a different color ( red instead of white like the rest of the #'s ) not sure what kind of a flash you have ... there might be a 'scale' on the side of the flash that tells you what aperature to set it at depending on the distance away from your subject. experiment a little bit ... depending on the flash at about 10 -12 feet you can set your fstop at anywhere from f4 - f8....
take what i wrote with a big grain of salt, since i have no idea what your camera & flash have. buy a roll or 3 of film - shoot it and see what your results are before doing anything important with your camera
ian gave some good advice - if all else fails, go the library and look for a book
-have fun -