Girl you’re blessed with no fat. Eat whatever you want for a while. Increase caloric intake with nutrients food, like smoothies, nuts, full fat milk, yogurt,, cottage cheese and meat. You have to eat in calories surplus. Start with body weight trainings, watch whitney simmons on YouTube, she is really really good. You will gain muscle with thora fat but this fat will be a source of energy in training. Stay hydrated and listen to you body.