Assuming you purchased an OEM remote (the only kind that will work)...you turn the ignition on/off five times, leaving it on the fifth time. At this time the LED on the top dash (armed/disarmed indicator)will flash and remain on. At this time, press either the "lock" or "unlock" buttons, doesn't matter which one. The receiver located behind and to the right of the glove box will remember the new code. The receiver can remember up to three codes. BTW, some cars are fussy and give the owner a rough time...if the LED doesn't light up and remain on, there is no point in continuing. Some owners (including myself) had to give it two or three tries before the alarm system co-operated! Good Luck.