Muscle building diet. Building results?

Hello, I am 27 years old Male with height of 5'7. I weight 66 kgs and don't have any allergy or physical abnormalities. I am a working professional & I've been exercising for last couple of years, but sometimes due to busy lifestyle, hectic office hours, missed exercising in the middle period. Now I have determined to exercise regularly, no matter what. I want to develop a good physique and build some decent muscles. I concentrate for protein rich foods for the same like eggs, sprouts, chicken, peanuts, etc. I take milk before sleeping daily. For effective muscle building, my gym teacher has suggested me to take some protein supplements. I have seen body builders taking it & heard sometimes that it's not good. Can you please guide me on this (mentioning what is correct, is it good or bad) and if possible suggest a good supplement which I can start taking for effective muscle building results?