namasthe yaar. You need to give us your full information like your height, weight, bodyfat %, and weight lifting experience. Also, at your age, you are probably too young to begin using any type of steroid.
I don't think you are too young to do this as others have said and I would be glad to help but you need to give more info then asking for a sust cycle. How is that going to help get you on stage? If you really want to compete there is a lot that goes into it and usually people will plan their drugs, diet and training ahead up to a year.
You're 18. If you're not making gains then your diet & training are for shit. Learn to eat & train correctly and then ask for cycle help when you're 25.