They are right about not doing just one cycle and that you need to eat more. YES YOU WILL GAIN BODY FAT BUT, with your metabolism, you will lose it just as quick and afterwards it will be muscle and you will weigh more. I used to be 150 and I gained 20lbs of muscle just using creatine, weight gainer, and a bigger grocery bill. I didnt worry about the fat because Im sure you burn it off quicker than you will put it on. So here is the advice you are asking for from someone with the same body type as you.
Start with 20 amps of Sustanon 250 mg per 1ml.
50mgs ED of Dbol for 4 to 5 weeks. About 400 tabs.
Syringes 3cc
22gg needles about 1 1.5 inches long
Thats about it. That is as simple as I can make your first cycle.
After about 3 weeks, you will love the results and will come back to the board asking advice on how you can run your cycle longer.
I cant stress how much you need to eat everything you see. Dont worry about getting fat. There is stuff that will help with that later. I promise.