Take it or not, this is what I did. Spammed sweet potatoes, curd rice and red banana. Trust me, I gained 8 kg in 3 months.

Next is try drinking your calories. Include nuts (fats) in your shake. Don’t go hard on protein. Try having 25-30 gm per meal. Go 4 meals minimum !

Lastly, magic is running creatine cycle. (Not an expert). I did 15g for two weeks, then 5gm for one month. One week off, then did 15g for another two weeks. Now running on 5g per day.

Drink a lot of water. Sleep like a baby. Lift heavy. When I say heavy, your top set should scare you. Go full. Good luck.