The outside of the foot can be used to make a pass, control the ball, or take a shot on goal. It's a way to flick the ball onto a teammate, control the ball while keeping a defender at arm's length or push the ball past the keeper into the net.
Play from the 1M line and start the drill by passing the ball into the Spot so it comes back to you on the volley. Turn to the side and pass the ball back into the Spot with the outside of your foot. Repeat this without letting the ball bounce. After 5 repetitions swap to your other foot without letting the ball bounce. See how many times you can do this in a row.