Two players stand on attack lines at either side of the net, while a third player stands between them at the net.
One of the players at the attack line passes the ball and then receives it back from the player in the middle, who now crosses the centre line, ducking under the net, before doing the same with the other player.
New hitters rarely miss because of their arm. They miss because of their feet. Build a reliable approach, then time it with your setter.
When your hitter gets stuffed, five teammates standing and watching is how you lose the point. Good attack coverage turns a blocked ball into a second swing.
Coaches spend hours correcting arms in serve receive when the real fault is almost always the feet. Fix the movement and the platform fixes itself.