Hi Keira,
To start off with you could just include the one ball, this will allow players to get used to the movement required.
As your players become more comfortable, you can progress the drill by adding in another ball or two. Encourage players to carry out the drill at speed and keep a continuous flow. Including a couple of balls also prevents players from standing around due to the quick rotations, everyone will have plenty of time on the ball!
Hope this helps!
Archie
