Eating, is a fundamental part of packing on muscle. You're in the right range for protein, over doing protein aka 100g+ a day is a total waste.
One warning i'll share is to only pack on as much muscle as you want to maintain. If you weight lift for a year or two then stop it sort of turns to fat.
OH and you said you're on the lean side already. You won't pack on gains at the same rate as someone who's already got a little heft to them.
And the final thing I'll part with in this post is be aware of plateauing. Confuse the shit out of your muscles and they will swell.
ps. do pushups, sit ups and pull ups every day. These don't necessarily require rest days.
I also do a ton of cardio in the summer. cycling and walking.
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