1) in pairs the players stand on the baseline on either side of the net. 2) Players then serve from the baseline attempting to place the ball just beyond the net so it drops no further than the attack line.
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.