klostman,
How old are you? How much do you weigh?
Probably a youngster....us old geezers have to worry about keeping weight off. Years ago when I was playing football and still very active, I and my roommate would drive to the 39c hamburger stand buy a dozen burgers each ..........for one meal. Man, these days if I even smell a McDs meal, my butt starts to swell. Even bigger.
Anyway, to more directly answer your question....don't concern yourself so much with gaining weight...instead focus on gaining lean body tissue. I suspect that is what you want anyway.
This is what I suggest: focus your lifting routines on core lifts and power lifting....BP, decline press, squats, hip sled, lunges, power cleans, deadlifts, etc.....lifts which utilize large muscle groups. The set/rep pattern you should utilize is 3-4 sets with 6-9 repetitions at about 70% or so of your 1RM. The last few reps should be tough to complete. Lifting in general will give you certain, specific results dependent upon your set/rep pattern and your level of exertion.
Regarding protein....in most cases excess protein either gets flushed down the toilet or is stored as fat. Normal folks use about .8 - 1.6 grams/Kg of body weight. About the size of a hamburger pattie. However, if you spend any time exercising, whether it be lifting or running, your body can use the extra protein. Lifters generally can use from 2.2 - 4.0 grams/Kg of body weight, depending on how often and how intense their workouts are. So, to shorten this up a bit, protein powders do work, but, use them according to your level of exertion.
If you have a gym nearby ask them if their instructors are certified by either NSCA or ACSM. If they say "huh?" you would be wise to continue your search. They can likely more directly and instantly answer your questions.
If you want more details, feel free to PM me. I would be glad to help. I do this for a living, been at it for 20+ years or so, got a few extra initials after my name, blah blah blah.