This really depends on what outcome you desire If you are skinny incorporating high calorie nutrients like(olive oil, nuts, salmon, beef) if you are rather fat consider eating less calorie dense foods like (potatos ,Joghurt chicken fish)

I would use very high protein foods with low calories that make you feel fuller for a longer period of time. For example tuna, chicken, eggs, Joghurt, fish, prawns, protein powders. Also make sure to drink enough water throughout the day as this can often lead to you being less hungry.

I would advise a 200-400 calorie surplus. If you start to see that your progress slows down adjust the calories.

You need to implement higher volume into your arm workouts. Another thing that helps is to go very heavy to get maximum muscle stimuli (4-8 reps). One very important aspect that helped me a lot was to train with for example arnold split providing you with a full day where you only train arms giving you that extra focus to grow every part of your arm.