for excercise you should focus on gaining muscles..by lifting heavy weights: 6-10 reps, 3-4 sets with 1-2 min rest in between. Squats, lunges, bench press, push ups, dead lifting, pull ups are the excercise for you. Aim for strength training 3-4times week on every alternative day, Go for short cardio session for 10-20 min twice a week.
as your body type have high matebolism rate ...which mean your calories are burnt up really quick...you should consume about 700 to 1000 calories more than what you body needs for maintaining your weight. Go for 50%carbs , 30%protein, 20%fat. Since your body burn energy too quickly you should fuel in more frequently...eat every 2-4 hours
my source of this learning is google and youtube....you can reseach more on it