Ok I understand how to do the avatar thing but I dont know how to have a signature. Please help.

You have to have been in the first 1000 people to sign up for the site, otherwise you have to buy one.

How would you know if you were the first 1000 people who signed up?

Well, if you click on yourself and view your profile, it says 3402, so you aren't able to get a signature without buying it, sorry. :(

Actually, there was a cut off date in which all new accounts made after a certain date no longer recieved a few sig. You can find info on how to obtain a sig on the front page. It's about $20 USD a year which goes to help keep the site running.