1) In pairs the players stand diagonally across from each other on either side of the net. 2) Player 1 then serves crosscourt at the same time as player 2 (the balls should cross in the air). 3) Each player catches the ball and repeats step 2.
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.