I learned of the circuit well over 10 years ago, although the original article is no longer online, Joe DeFranco designed this circuit for professional athletes who are tested on the bench press, and he does not want them to shoulder press heavy at the same time, yet still wants shoulder development.
This circuit he devised I have used in hundreds of training sessions, it’s simple, it’s effective, and it requires very little equipment, you only need light dumbbells and some standard plates
I have made modifications over the years, I do the overhead Raise is standing, I have replaced the overhead press with a posterior deltoid raise at times, But the original circuit is still something I schedule regularly into my programs
The rep scheme is 20 reps, 15 reps, 10 reps. You repeat the circuit 3x times. That means 20 reps for ALL the exercises on the first round, then 15, then 10 (for reasons unknown people get confused as hell by this regardless of how many times you explain it)