It's really not that difficult. You wanna grow you gotta eat. If you think you're eating enough but still can't add weight then its simple..... you eat more.
Protein shakes are decent to get a quick source of Protein in you but you should never replace whole foods/meals with shakes. If they were all so brilliant at getting the body we wanted do you really think they would be as cheap as they are?
Same with all these fad diet plans/shakes that are going around.. Juice Plus/Herbalife etc all a load of crap.
Serious eat like a king and train like a mother henr!
Various supplements will aid in recovery time and getting essential nutrients/vitamins to your body where you may struggle to get with whole foods, but overall just eat and lift bro. You'll be weak as a louse at the start but keep at it and don't let anyone put you off what you're gonna be doing. Everyone started off skinny one day.