I'm new to all this, maybe you guys can help me out?

Anyway I have a iphone 1st gen. 8gb, I've already quickpwn it, and I need help activation, I have 2 unused att sim cards but those are no good after I've quickpwn it??? right??
I have no idea what type of sim I need.. And do I just put the sim in the iphone and blam.. I can make calls?? or is there more to it??

Please any help out there??
Thanks to all who help with my last question.. All replys helped me..