The backcourt players performs pressure on the defense.
First defending backcourt meets the attacker and tackles the ball holder.
The defending center covers against diagonal passing. The other defending backcourt covers CR.
The ball is now passed to CB, who moves in.
The defending center moves out and tackles and the first defending backcourt falls back to release 2nd defending backcourt covering the CR.
The ball is sent to the 2nd attacking backcourt, who moves in.
The defending center slides diagonally backwards and covers for diagonal passing and the 1st defending backcourt covers the CR.
After this the ball is returned using the same pattern.

The most important in this exercise is to prevent a free pass to CR.