Dead battery on 2007 ultra classic. i need to know how to replace it

Your battery is located under the seat. "Always" disconnect negative first, as to lower the risk of grounding your screwdriver when moving to the positive cable. When reconnecting do "Positive" first, for the same reasons discribed. Dresser batteries are the largest an heaviest so it's just a matter of finding a good place to lift after it's disconnected. Also, It may be wise to have your charging system checked if you ride this bike all the time, as your battery should have lasted longer.