Passport drill video on their website. I like it and plan to modify it for Red and Orange ball players to get them comfortable with coming to the net.
It is a simple activity, as you will discover if you watch the video. Coach is at baseline. Player is across the net at service line. Coach feeds a ball that bounces in front of player. Player hits it after it bounces, comes in, taps net with racquet, and returns to service line. This reinforces the idea of following a short ball in.
Player takes ball out of air (volley) rather than letting it bounce before they hit it.