Well first of all, you must have a goal in your mind, don’t you? Handstand, or maybe muscle up? My advice is to start working slowly toward whatever your goal is, by doing progressions. If you can give me some more information about what you wanna achieve, I can help you a little more. And about diet - I started skinny, but over time I ate more and more, including protein, carbs and fat in my meals. Eggs or oats are great for breakfast, and in the afternoon you can either go for steak, ground beef or chicken, combining them with carbohydrates for energy, and fat if you wanna bulk.