If you only want to incorporate the primary muscle groups, then your workout will look like this:
Workout 1: Back (20 minutes)
Workout 2: Chest (20 minutes)
Workout 3: Legs (20 minutes)
E.g. Tuesday you trained your back. Wednesday you trained your chest. Thursday you trained your legs. It’s now Friday, but your whole body is sore. What do you do? Simply rest and allow your muscles to recover and grow. Enjoy the day(s) off.
There’s no need to stick to the workout order either. For example, if your back and legs recover quicker than your chest, simply skip your chest workout and workout your back and legs until your chest has recovered. Don’t postpone your other workouts while you’re waiting for a particular muscle group to recover.
As your body gets used to training regularly, you’ll find you won’t need so much time to recover, especially if you’re incorporating a good amount of protein in your daily diet.