If you want to add muscle fast to your upper body you will need to do the barbell bench press (I also really like dumbbell presses also)But for starters lets learn the basic bench press first I am always amazed on how many people do the bench press wrong. They bounce the weight off their chest, arch their back off the bench all so they can tell everyone how much weight they can bench press.
If you want to add muscle mass to your chest and upper body you are going to have to leave your ego at the door and learn to do this exercise correctly The first thing you will need is a spotter,this is a person who will stand behind you in case you are unable to lift the weight. (remember safety first) To Start I recommend a grip on the bar a little wider than shoulder width apart. (Later you can adjust the grip to where you feel most comfortable).
Never just jump into the bench with as heavy weight as you can handle,if you do you are just asking for injury and I have a bad shoulder and had a pulled pec muscle to prove this. Start with a warm up weight you can easily handle for 15 to 20 easy reps. Perform 2 to 3 sets of this about 1 minute apart. Lower the weight to your chest. You should lower the bar to nipple level, just in contact with your chest. Then pause for 1 second and then push the weight back up. Avoid bouncing the bar on your chest as this may lead to injury and take away from the effectiveness of the exercise. Raise the bar to near full extension. Do not raise your back off the bench. Stop just before full extension to avoid the injuries that can come from locking the joints and pivot points.
Always remember if you want to add muscle fast concentrate on performing the exercise properly and do not ego lift.
Now it is time to add more weight to the bar(you need heavy enough weight if you want to stress the muscle so it will grow back bigger and stronger,this is the way you add muscle fast. Add a weight to the bar that you can manage about 8 to 10 reps before you cannot lift the weight any more. rest for 1 -2 minutes then add a little more weight so that you can only lift the bar about 6-8 reps. rest the same amount of time (1-2 minutes)then add just a little weight where you can only get 4-5 reps. Now by this time your muscles will be tired. So I would not add weight to this set,just rest about 2 minutes then hit the reps again,you can once again get 5 reps add just a tiny bit more weight rest for about 2 minutes and do one more set of 3-5 reps, try to go until you cannot lift the bar any more (this is where your spotter comes in,he will help you if the weight on the last reps comes back on you and you cannot get it racked).