Op, bullshit aside dont listen to cunts, especially slothguy. You dont have a base(little to no muscle) to cut down to. Therefore you really just need to pick a solid meal plan and also stick with a good training plan.
Easy steps for beginners: take you body weight X 19- this is a base on how many calories to be taking in a day to gain mass. take body weight again X by 1.5 this is the minimum amount of protein you should be taking in a day. ex: if you weigh 200 pounds be eating 3,800 calories and 300g of protein per day.
You definitely need to find a good training program, perhaps a simple 2 body part per day split EX: M-chest/tri T-back/bi W-Leg/shoulder repeat. There are many different laid out plans on this site so just look around. Find one stick with it for a year and then come back.