What guys above said.
If you want to do 3 days with upper body focus, here's possible schedules:
chest+delts+triceps+back/biceps+forearms+calves+hamstrings+quads/chest+delts+triceps+back (doggcrapp base routine)
chest+back+delts/legs+arms/chest+back+delts (what AlphaBettor said)
chest+delts+triceps/legs+back+biceps/chest+delts+triceps (push/pull, ABA)
full body/full body/upper body (upper body focus)
full body/full body/X (X= body part that you wanna focus on)
chest+back/delts+arms/chest+back (bro routine, no leg training)
and so on and so on..
"He never had the makings of a varsity athlete"