When I was first starting out years ago I did an excercise for each body part every other day. Not sure that is the best, but that's what I did.

Right now I'm trying to work through an injury so I decided to break it up by doing Shoulders, Back and Biceps one day and Chest, Triceps, and Legs on the other.

Once I get more to the intermediate level I'll do Chest and Triceps one day, Legs and Shoulders another, and Back and Biceps the third day. For this alternates the push pull muscles for those areas, except the Legs Shoulders of course. Also, alternate between which you do first because one fatigues the other, this way you can lift more with the first body part than you could if it was the second.

I'm sure someone with more info will chime in.