It would have been helpfull if you have had mentioned your weight and height readings. But anyway I will try to help you.
I would like to tell you what takes to gain weight healthy manner. It's should be 50% of you diet 30 % of sleep and 20 % is exercise.
Food should be more of protein that comes from eggs, green gram sprouts, rajma, soy beans, you can have eggs boiled 3-4 EGGS a day. Sprouts, rajma, soybeans can e had in form of salads,
Meat should be chicken mostly take mutton 4 servings per week which should be a fist full quantity.
Carbohydrates should be compound carbs which we get in all cereals, like wheat, jowar, oats, ragi, can be taken in the form of rotis of all the flours of above cereals, also go with ragi malt atleast 2 servings per day.
Along with all vegetables and fruits you like should be 5 servings per week.
Having yoghurt everyday will keep your BMR healthy, and also the nuts in the morning.
Glass of milk with 2 bananas twice a day.
Water should be 3-4 liters a day.
Sleep should be 8 hours a day but not day sleep. Do not sleep after having food.
Excercise: when you take good food you obviously get satisfied at Gym in lifting weights and your body will start changes and the changes you see will surprising you.
There is one thing called cheat diet that is you can cheat diet you are following and that should be on the seventh day you cam have food of your choice like junk or anything. Bit.only one day per week