Start by facing laterally to the speed ladder.  Lead with the foot that is closest to the speed ladder and perform the high knee motion the entire length of the speed ladder placing each foot in every hole.  Be sure to maintain an upright body position, bringing the knee up level with the hip, and pulling the toe up toward the shin.  Move your arms in a coordinated fashion with your legs as if you were running.  Perform the next repetition moving in the opposite direction.  Here you will be leading with the opposite foot .  Move as quickly as possible while maintaining control.