Guide me how to increase my weight

Hi there, nob.

First of all, do you eat regularly? If you want to gain some weight you mustn't skip meals. That means eating 3 times a day + two snacks between them. Usually, it's best to eat after 8 A.M. if you want to get some kilograms. From my experience, if you eat just before going to bed, that's certain way to gain weight. But, I had bad dreams, because food digested during the sleep. 

Also, you can eat food high in calories and proteins, such as animal fats, fish oils, peanut butter, junk food (we all know what is it :)), fried foods, sausages, etc. 

But be careful, because eating too much "heavy" food can damage you health in long-term.