how to program the keyless for my mustang gt 1997

I would like information and instructions on how to pogram my keyless remotes for mustang GT 1997 ?

I did the folowing but i have problem and i can't continue, do you know anyone what is wrong???..... "Cycle Ignition from OFF to RUN 8 times within 10 seconds, ending in RUN. All doors will lock then unlock to confirm programming mode (It doesn't respons WHY???). Press any button on 1st remote transmitter. Door locks will cycle to confirm programming. Press any button on 2nd transmitter ( up to 4 transmitters total possible ). Turn ignition to OFF. Locks will again cycle to indicate end of programming mode.

Please help me!!!
Thank you!!!