Welcome.
If you think you know what you need to eat to maintain, just eat that for a bit. If you maintain, and you want to gain, start upping the food until you get to a point where you start gaining. It's kinda simple, but not necessarily easy if you're not used to shoving in a lot of food. But, yeah. If you want to gain, you need to eat more than it takes to maintain. If you're lifting a decent amount and not eating waaay too much, your gains can be expected to be on the muscle/lean mass more than the fat.
Again, welcome.
