"I want to increase my weight - could you help me?"
I want to increase my weight which is 48 kg, I am 20 years old, could you help me?
Well, I'm not greatly well versed on nutritional information. My suggestion is go to a health food store that carries books, and look it up. Write down a list of recipes or menus that sound good to you.
The fastest way, of course, to manifest anything, is to see yourself, in your mind's eye, the way you choose to be, already, and to feel strongly how good that would feel. Really see yourself at the weight that you want to be. Put in clear details.
Another thing that you can do is simply state this: "I now set my apperstat to remain steady at _____ (whatever weight you want it to be)." The apperstat is the body's weight defining mechanism, so it's like putting a program into your body's computer system.