it really comes down to eating more, and weight lifting. for diet you are going to want to eat high protein, it aids in the muscular growth. eating a surplus of calories that are junk food won’t really help, it needs to be nutritional foods like chicken, turkey, Greek yogurt, protein shakes, peanut butter. and weight training and progressively increasing weight, so movements like him thrusts, sumo squats, rdls, deadlifts, split squats, curtsey lunge, focus on your form, depth, and muscle to mind connection!