There are three offensive players and three defensive players as pictured in the diagram
The ball starts at the top of the key
x1 is guarding the ball, x2 is in gap positioning, x3 is denying the post up the lane line
#1 passes to #2 and the defense jumps to the ball
x2 is guarding the ball, x1 is in gap positioning, x3 is in a 3/4 deny on the post
#2 passes the ball to the post
On the post feed, x3 slides behind the post and takes away the baseline shoulder
On the catch, x2 and x1 "dig" on the post
#3 takes two dribbles to the middle of the floor
x3 walls up
x2 and x1 "choke"
#3 passes the ball back out to one of the perimeter players, the defense rotates back, and the drill ends
Make sure to teach proper rotations, post defense technique, and digs/chokes
Move on the air time of the ball
Communicate everything