It is important that the defender learn how to use the correct way of side movement, which is never to cross the legs.
She follows the attacker with side movements and when the attacker jumps, the defender also jumps and tries to block the shot.

Remember that the defender must not jump at the same time as the shooter, but wait a little in order to be at her highest point when the shot is performed.
The defender must not push forward more than 1-2 meters so that the shot is performed just within the free-throw line.
It is not the meaning in this exercise to prevent the shot but to block the shot.