Sustanon 250= testosterone blend = 4 different ESTERS of testosterone = proprionate, isocaprioate, cypionate and decanoate (I could be a little off(mistaken) on these esters)
Learn what an ester is, and how it impacts the active time and half-life of the drug in your body.
Learn what PCT means, and then do some research on things called SERMS and aromatase inhibitors.
Now, since you are a 'hard gainer', tell us about your diet since your 'diet is on point.'
Please understand, we like helping people, but we absolutely loathe spoon feeding information to people. Many of us on here spent 50-100+ hours studying/researching these hormones and drugs, so it 'frustrates' us when someone comes on here and wants 'the key to the city' because he can 'buy some roids.'
Seriously, show us you want to do this right and we will be more than happy to help you.