2 players will attack 1 defender. After a shot has been taken all 3 players become offence and 2 defenders will run in to play a 3v2 at the other end.
Once a shot has been taken at that end. The 2 defenders become offence and 1 defender will run in at the other end.
This is a continuous drill, where each end the same thing will happen each time.
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.