needs some tips on gaining weight

Scale weight is made up of fat, water and lbm (of which only muscles are really going to go upBd down)

When you put on weight you add a combination of all 3

Genetics will determine where excess fat will go

Progressive resistance in surplus will help determine where excess muscle will go eg butt, thighs, abs...bodyweight programmes or real strength training programmes

you need to eat surplus calories

As you do so you should follow some form of progressive resistance programme to maximise muscle gain

Read the opening post here: http://community.myfitnesspal.com/en/discussion/10326769/are-you-a-hard-gainer-please-read/p1

Progressive resistance bodyweight https://www.nerdfitness.com/blog/2009/12/09/beginner-body-weight-workout-burn-fat-build-muscle/

But a programme like Strong Curves, stronglifts5x5 or starting strength would be more effective

Ensure Plus or the Equate brand from walmart (a little cheaper).
An 8 oz bottle contains 350 calories. Drink it right before bed. (cost a bit more than $1 a bottle)
High calories foods: peanut butter, avocado, all nuts, milk, cheese, meats.