Well, what type of machine did you get? A basic?
One tip which I wished i knew from the beginning:
when you expose the screen, make sure there is a few layer of paper or something that will soften the padded squares (where you put the paper that will be printed). If you don't you risk having them permanently as a feature of your design.
And another, don't bother to try to clean your screens, if it is not a limited edition and perhaps you plan to print it again, once you have finished with it for the day, put it in a zip-lock bag or cling wrap and pop it in the freezer. It takes it about 10 minutes to warm up again when you take it out, but the ink will be fine and the screen preserved.
Enjoy your printing and experimenting!