If you have remote keyless entry, press the lock and unlock buttons on your remote at the same time until your horn chirps twice. Then it's a fairly long process, but an easy one.
First: Make sure you're near a air compressor.
Second: After the horn chips, go to the driver's side front tire and press the valve stem to release air from the tire until the horn beeps. This could take anywhere from ten to thirty seconds.
Third: Repeat above step on the Passenger's side Front, then Passenger's side Rear, then Driver's side Rear, in that order. The horn should chirp twice again, this signifies the learning is complete.
Last step: Re-inflate your tires to the recommended pressure and then remove the keys.
I hope this helps