Hey! Welcome to the forum
Well, there is always something new to learn and the diet you need always depends on your body, since everyone's different
It will take some time to figure it out, but I'd recommend you to start reading other famous bodybuilders articles/books on how to make a good nutritional program, etc. Myself, I try to eat mostly whole foods, especially a lot of fuits and veggies. For protein I eat a lot of lentils, beans, bread, nuts,peanut butter, seeds and some veggies (especially kale and spinach).
I know that in US it's very popular to take some supplements, but I prefer not to. I am trying to be as natural as possible.
Well I wish you to be patient and good luck!