Yeah it's not rocket science. Eat more calories/protein (e.g., lean meats), do more compound lifts (which will tear your muscles). The extra protein intake will build those torn muscles stronger when you rest/recover. You just gotta eat WAY more than you do now.
Tbh you will probably have a tougher time eating more than you think you should than lifting weights. The lifting part will be relatively easy as you're athletic and used to working out.