I'm a biochemist who also studies exercise science, I'll try my best here.
Starting out it is best to stick with a rep range of around 10-20, broad I know but research has shown that any rep range that is within close proximity to failure will build roughly the same amount of muscle as any other rep range. 10-20 is also not too heavy meaning less likelihood of injuring yourself.
The eccentric portion of the movement which is the downward or lowering portion of the exercise where the muscle group is eventually placed under a loaded stretch is the most hypertrophic portion of the movement, meaning it will grow the most muscle, you are also close to 30% stronger in the eccentric. Go slow on the way down and explosive on the way up, and make sure you get a deep stretch at the bottom, the loaded stretch is critical for maximum muscle growth as it allows for stretch mediated hypertrophy to take place.
So now we have the execution of the movements taken care of, we can now look at exercise selection:
Arms
My personal favourite movements for biceps include: Cable straight bar curl, preacher curl, dumbbell curl, hammer curl of brachialis.
For the triceps I would 100% suggest the dip - brings triceps to fully stretched position, high overloading capacity, high pec major activation as well.
I would also suggest the rope pulldown, straight bar pull down, and skullcrushers.
Back
Best exercise in the world for the back is the pullup - highest measured lats activation, highest measured biceps activation, high overall core activation, high overloading capacity, it has it all. If you can do a normal pullup then go with assisted until you can work your way up.
Include also a horizontal pulling motion of your choosing like a seated row or a one armed row.
Cable pullovers are also mighty for building the back.
Chest
The chest is often overtrained to death when it really doesn't need to be in order to grow. Perhaps a total of 3-4 movements are absolutely necessary for the chest - An incline pressing movement, a flat pressing movement or a dip, and a fly variation for potentially hitting the intercostal fibres of the chest. That's really it. No need to burn your chest to the ground with 30 sets per workout.
I do the dip, incline smith machine press or incline machine press, cable fly and that's it.
Delts
Delts are massively important as they give you much more width adding to a greater v-taper.
there are 3 heads, the anterior, the posterior and the lateral heads. The anterior or the front delt will receive sufficient stimulus from pressing movements training the chest so it does not need to be trained separately in most occasions.
For the side delt you want a simple lateral raising variation, 1 or 2, spam them hard as they are fantastic for the delts.
The rear delt is often under looked and undertrained but it is extremely important for the aesthetic of your delts, it makes them pop from the side giving you that real 3D look. A rear delt fly variation is all you need, a reverse pec dec or a rear delt fly on the bench with dumbbells or a cable fly, one of these will suffice
Quads
DON'T YOU DARE SKIP LEGS. Quads are an extremely aesthetic muscle group and if grown then they can look absolutely stunning. You really have to train them hard in order to grow them, but the exercises you need are very self explanatory.
Leg extension, trains them in a stretched position position.
Squat, trains them in a synergy with muscle muscle groups of the legs, perfect starter.
Sissy squats, takes the quads to an incredible stretch.
Perform all these exercises with the aforementioned form in a progressive manner and in a few months time you will thank me.
Hamstrings
Also often under looked, if you want big legs then you need big hamstrings. The hamstrings consist of 3 muscles: the semitendinosis, the semimembranosus and the biceps femoris. In order to train all 3 you need a movement that involves hip extension and a movement that involves knee flexion.
The hamstring curl, bog stander hamstring exercise that works 100% of the time.
Romanian deadlifts of stiff legged deadlifts as the train the hamstrings in a lengthened position allowing for stretch mediated hypertrophy as well as involving hip extension.
Train every muscle group a minimum of twice per week, some muscle groups can take more(just ask and I'll tell you even more if you are interested), leave your ego at the door when you enter the gym, and make sure you are getting stronger over time.
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There are other muscle groups I didn't mention that will also have to be trained but as a beginner it's less about what you do and more about DOING it and not skipping sessions. Create the habit of going to the gym and never missing a session and then you can look into training different muscle groups directly like the traps and the calves and forearms as part of an all encompassing program. But you first always have to build a foundation.
Ask me whatever you want and I'll try to answer to the bets of my abilities and feel free to challenge anything I've said in the post, I love to debate and/or be corrected if I am wrong.
