How do you the zombie ride in dead rising

Zombie Ride
Jump toward a horde of zombies then tap FORWARD + A to have Frank walk over the top of their heads. This can only be done on zombies that are very close together. He can also jump from the top of their heads while walking on them. In order to do this move properly, you must be close enough for the zombie to grab you, literally touching the zombie, and then press hold forward and jump
then Frank should step up to the zombie's shoulder. If you jump too soon, Frank will merely jump straight toward the zombie and will likely get hit.