Post player starts with the ball on top. Passes to the wing then runs to set a screen on the ball. Have a coach/player/manager on the opposite wing. Have someone in the lane with a blocking dummy. This can put resistance on post player.
 

The post man dives to the opposite block. Go underneath the defensive pressure (blocking dummy) or defender. Ball handler comes off the ball screen and makes a quick pass to the opposite wing. Wing then throws the ball to the post man establishing position.