You have to eat things that are high in protein, high in good fats and high in carbohydrates, which will make the food high in calories. You should be getting a good caloric surplus each day. This means that if you were to eat lets say 2500 calories per day to maintain your weight, you would be eating 2700-3000 calories to bulk at a slow but steady rate. The types of foods that you should be consuming include: Meats, Poultry, fish, nuts, potatoes, sweet potatoes, brown rice, wholewheat bread, nuts, seeds, eggs, milk, cottage cheese. You should eat about 5-6 times a day while you are bulking, since it is easier to eat small frequent meals instead of eating 3 huge meals.
I can make a meal plan for you just for one day:
Meal 1: Oatmeal with blueberries, glass of milk and whatever you like to have with it.
Meal 2: Chicken breasts with a salad
Snack: Handful of almonds/peanuts
Meal 3: Baked salmon or oily fish with roasted potatoes
Meal 4: Protein shake or if you are not having shakes, 4 eggs with wholemeal bread
Meal 5: Cottage cheese (flavour with whatever to make it taste good)
Something like this, but tinker around with it until you find what you want to eat, but if you like it how it is, then keep it like that.