Start with feet just wider than shoulder width apart; take the first step with the foot nearest the intended direction, then take the next break step and bring the other foot round shoulders square to the net and jump to block.
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.