ok, i do need to learn how to change my rear tire. front tire is a quick change.

I got my Trainer (mag) last night. now i have one Question. my Trainer has 5 speeds on it, and so what gear am i supposed to ride my bike in while on the trainer? does it matter? am i supposed to change bike gears while on the trainer or not? thanks.

the Trainers that look like a Bike are out of my budget. this is a hobby right now, but i also have a horse that i ride, so Biking cannot be my MAIN hobby. i don't have too much money to play with, so i have to be cheap with the bike.