Well, you are in the right place to learn, search my young friend and you shall find the secrets to all of your answers. I would start by browsing the nutrition and supplement boards do a search under fat loss supplement or ketogenic diet.
Lots to learn, using roids or PH at your age can stop your growth and cause lots of problems for you.
I remember when I was your age, around 16 actually I dedicated my life to BB and read EVERYTHING I could about it. I got up 268# with abs before I ever touched a hormone. Back then all it took was diet and proper training and of course dedication above all. I graduated highschool at 6-3 185# a few years ago I had my 10 year reunion and was over 6-4 & 100# heavier.
There is so much to learn I could never teach you .05% of it it, is something you will have to do for yourself. Good luck, it's a lifestyle and it will consume you if you let it as Yoda said there is no try, only do or do not
BTW I would only recommend a keto diet if you are very overweight otherwise eat a nice clean diet and do some cardio, tons of info here.