Players work with a ball each and pass the ball against the wall so that the wall bounce passes the ball back to you.
Repeat.
Start with the ball close to your chest (fingers should be spread around the ball).
Step into the pass and extend your arms as you push the ball towards your team-mate.
Look at the receiver as you make the pass (not at the ball).
Finally remeber to straighten your wrists and follow through (the pass will go where your fingers are pointing).
Rebounding is the least glamorous thing in basketball and one of the most decisive. It is also almost entirely a habit, which means it is entirely coachable.
Good spacing is only the start. The best modern offences teach players to attack the defence's rotations and play in a permanent 4-on-3 - here is how to coach that read.
The ball screen produces almost half of all professional offensive possessions, yet most teams still teach it as a memorised play. The modern approach trains the read - giving players a framework to decide based on what the defence does, not what the coach called.