Stick to compound lifts if you want to see the biggest gains as a beginner.
Bench press
Squat
Deadlift
Pull up
Rows
These exercises will target mutiple muscle groups. Use free weights. Start with light weights to ensure correct form and gradually increase by 1kg at a time, only increase weight when you can achieve specified reps per set with correct form.
The most important thing is to get your nutrition right. If this isn't right you will struggle.
With perfect form they are harmless.
Be careful with preacher curls especially if you're new at this. Many believe they're bad for the back and shoulders.
These are the exercises I use to build chest/arms and I gain great results from them.
Chest
Incline barbell press - 3 sets, 6-10 reps
Incline dumbell press - 3 sets, 6-10 reps
Chest dips - 3 sets, 8-12 reps
Biceps
EZ bar curls - 3 sets, 6-8 reps
Hammer curls (dumbbell or bar) - 3 sets, 8-10 reps
Preacher curls with EZ bar - 2 sets, 6-8 reps (be careful on how far you extend your arms).
Triceps
Rope pulldowns - 3 sets, 8-10 reps (your back should not be doing the work)
Tricep dips(hands on bench, feet on chair) - 3 sets 8-12 reps (add weight as you progress)
EZ BAR skull crushers - 2 sets 8-10 reps
Remember you will only grow if you are eating sufficiently and eating more calories than you burn off. If you are just looking for size and don't care about definition then eat LOTS of carbs. Also you will not build muscle with poor form. The weight doesn't always matter, start light in order to perfect your form then you will be able to push heavier in future and help to prevent injury.
Finally - CONSISTENCEY IS KEY!
There are no best workouts. Every bodybuilder has a theory. There are many routines that will work, most likely, not just one. If you use a gym weight machines have one benefit, in that they are calibrated to give you proper technique and show you right on the machine usually what muscles they're working. If you want to do free weights, can you afford a couple of sessions with a personal trainer? Or just watch the folks with the best definition where you're looking for it and ask them their routines.