Start with a search on this forum.
But in a nutshell, the quickest ( not the best) way is to remove the IAC using a torx driver, spray the heck out of the hole it came out of with throttle body cleaner, spray the IAC, ( dont try to adjust it), spray the inside of the throttle body by holding the butterfly open and sticking the spray nozzle into every crack and hole you see in there. Replace the IAC, let it sit for 15 min to dry out a bit, then start it. It will run funky for a little bit as the liquid burns off....but it might help your problem.
The BEST way is to remove the throttle body and clean it thoroughly.