Does anybody know how to reprogram a 02 yukon keyless enrty

Does anybody know how to reprogram a 02 yukon keyless enrty system with used remotes I bought?

Close all the car doors.
Insert the ignition key into the ignition lock cylinder.
Press and hold the door unlock switch.
While holding the door lock switch in the unlock position, cycle the ignition ON, OFF, ON, OFF.
Release the door unlock switch. The doors will lock and unlock to confirm the program mode.
Press and hold the LOCK button and the UNLOCK button at the same time on one transmitter. After a delay of roughly 15 seconds, the doors will lock and unlock to confirm the programming of that transmitter.
Repeat the last step to program up to four transmitters.
Turn the ignition switch to the RUN position to exit the keyless entry transmitter mode.
Operate the transmitter functions to verify correct system operation.

you have to take it to the dealership and have them do it for you

See if your local library has service manuals for 02 Yukon. Most will tell you how to program your remote. it's typically real simple. Like jumping two wires, turn the key on and push a button on remote then unjump the wires. Each make of car is different. I have done some number of by checking the library..