Their are hundreds of training programs and not all of them are for everybody. That being said, I also do a four day routine and will lay out what I do most of the time.
Day 1: Chest and Tri's, and cardio 20 min
Day 2: Back and Bi's and cardio 20 min
Day 3: Legs,Legs,Legs
Day 4: Core work and calves and cardio 20 min
I also hit calves on chest or back day...Start reading about different routines and split routines. This works for me because of my work schedule...Good Luck and lift hard or go home but be smart....lol