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.
Good team defence is five players guarding the ball, not five separate one-on-ones. The shell drill is where that starts, so here is how to teach help-side positioning and rotations from the first week of the season.
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.