Rob,
The best thing you can do is to look at some of the basic tutorials right here on perlmonks or elsewhere on the web. There are gazillions of them. If possible, grab a copy of Learning Perl or any other beginner's Perl learning book. Do a few tutorials... should take less than a day. Your current question will be answered and then some. Btw, you are making a great start. When I was 12 I had no idea what a computer was...