How to teach team defense?
You have to teach help defense.
This means you have all of the players working together. If one person gets beat, then someone is there to help. Then everyone rotates toward the basket.
But, that all starts with the players being in the right weak-side position.
In help defense, the player 1 pass removed can hedge or jump to slow dribble penetration. Unless that player calls “help” the defender covering the ball is responsible for recovering to guard the ball. If the player 1 pass removed calls “help” it tells the on ball defender to rotate to the help defender’s offensive player.