Coolant change HELP

Hello all, this is my first post on this site, but have used it for help many times. Anyway I'm wanting to drain, flush and refill my 1998 cavalier z24's coolant. I found the drain on the radiator, but only 1 or 2 liters of fluid comes out. The chevrolet place said the only way to do it was a machine they had and it cost $109.95 to do it. I call B.S. so I figured I would come to the best site I know to ask how I can do this myself. Please someone walk me thru this as if I'm a idiot, LOL, no really please explain the steps if possible. Thanks in advance.