The first thing you must obtain before roll stepping, is comfortable tennis shoes or the proper marching band shoes. You also need to be able to understand proper attention. Heels together, toes apart, chest out, stomach in, shoulders back, chin up, and eyes with pride. This is how you stand in attention, this will help you obtain the proper roll step.
Now that you have the proper attention stance, you can start roll stepping. The first movement is picking up your left foot slightly off the ground and placing the