A 3 day full body workout is a great start towards muscle building. Typical 3 day full body workout would be scheduled around Mondays, Wednesday and Fridays. Though there's a lot of workout you can try.
Here's a few to start off with:
Day 1: Squat focus. Workout such as squat, incline bench press, barbell row, pull-ups.
Day 2: Bench press focus. Workout such as bench press, pull-ups, dumbbell row, leg press.
Day 3: Deadlift focus. Workouts such as deadlift, military press, pull-ups, machine or cable row.
When starting off, ensure that you warm up. Start off with smaller reps and smaller weights. Once you are settled with the reps and weights, increase them gradually.
