Weight gain. Steps that i need follow,

you can opt for natural soy protein. muscle building will require high protein intake. eggs, meat, soya chunks, paneer etc are also natural resources. whey protein is not a bad thing until and unless you dont workout enough to utilise those amines.

First question""why do u want to look bulked up?"" There is no need to worry about weight unless medically advised! Aim for fitness rather than weight. Fitness is considered a lot more attractive than weight.

Our human body is categorized into 3 body types. Vaata / Pitta / Kapha . Usually vaata predominant people are skinny. In order to gain weight, you first have to decrease those factors which cause imbalance of vaata dosha ( for example too much  travelling, eating refrigerated stuff, staying in cold, lack of proper sleep, waking up late nights, spicy food, tastes like bitter ( coffee ,tea) & a stressful job all increase vaata dosha. On the other hand milk products( especially cow )  A regular self oil massage with sesame oil ( abhyanga ) is very helpful in decreasing Imbalance of Vaata Dosha. Doing self abhyanga daily with ashwagandha oil also increases muscle significantly. Protein powders like whey, soy, casein etc are hard on stomach, liver , kidneys & other organs. You might end up in trouble if you don't set your Vaata dosha & start taking supplements. Go for a full body check up to know any deficiencies & consult a good Ayurvedic practitioner. Good luck!