if you've never trained with any set goals before, you're a beginner.
follow WS4SB to the letter.
eat the dead animal flesh of your choice.
eat 1-1.5g protein per lb of bodyweight to start, fill in carbs and fat as needed to gain at least 1-2 lb a month on the scale and however much weight on the bar that WS4SB tells you you should be adding every training cycle. if these two aren't going up, eat more. eating more and making progress is much better than eating less and not going anywhere.
protein powder, apparently you get what you pay for. personally I'd prefer getting something like a whey concentrate or hydrolysate just because you're fairly sure the manufacturer hasn't added much crap to it (sugary carbs, fat) if I could use whey/casein without blowing up and breaking out. turns out beef protein powder works fine for me.