I've found 6 total reps to be a great number. There isn't anything magical about it, besides convenience. It allows for a lot of variation, such as...
2 x 3 [2 sets of 3]Since the volume is low, it serves for a quick workout on compound lifts like deadlifts, snatches, overhead presses, pull-ups, etc. The low reps per set means the intensity can be a moderate or high level.
3 x 2
6 x 1
1 rep, 2 reps, & then 3 OR 3, 2, 1
1, 2, 1, 2 OR 2, 1, 2, 1
It's easy without having to spend a significant amount of time for the session. Other numbers can be used, but higher numbers lengthen the workout's duration. Trainees also tend to overdo it on volume hence why I prefer the number to be low.
Do a few warm-up sets and give it a try.