Well, thats my territory!!!!
.I have been a bodybuilder for years. My advice to put weight on, isnt just to lift weights, cos what you will do with that is put air between your bones and muscles. What you need is an special diet based on proteins and opposite i would advice to someone who wants to loose weight, you need to eat carbs. Of course, when i say carbs i am not talking about "fast burger food" ok. I am talking about a nice steak or a nice dish of pasta. Carbs that you can burn easy and dont keep it all of them as reserve in your body. The main thing is not put too much weight on you. The secret is a convination between a good diet and the right work out. You need work out your whole body at the same level; work out your legs and arms the same level. Sounds ridiculous but legs are very important and you need to exercise them as well. Sometimes ask to a personal training or to a person from the staff gym can be not the right solution. The most of them dont know what they are talking about, and they can even give you a work out rutine when they will kill you lifting weights and you would have to leave it in a couple of months cos you are tired. Go to a nutritional doctor and he will give you the right diet after he makes you blood test and stuff.
VERY IMPORTANT!!!! Give to your body the right rest. Dont go to the gym every single day try to look like Jean Claude Van Damme, that will be impossible.Those guys take gym drugs. DONT TO THAT!!!.
Eat 3 times a day, help your meals in the morning and at the lunch time with proteins milkshakes (Tremonti put weight on him with that at the buigining of Creed cos he was too skinny) and fill them up with water insted that with milk at the buigining. I am saying that cos maybe you can have an excess of put weight on you.
About the right work out, go to a gym where you know you can trust the staff.
Any other thing Aussie pm me or ask me in this topic.
I hope i helped you.
xxxGabixxx