It takes time to gain muscle, and it requires reasonable exercise and regular diet. Do muscle training three or four times a week, preferably in the gym. If it is inconvenient to go, you can also do dumbbell training by yourself. Do 3 to 4 groups for each training action, 8 to 10 times for each group, and gradually increase the brightness between each group. Don't practice too much a day, or it will be counterproductive. Protein should be supplemented in diet, and milk and boiled eggs should be kept. Protein should be replenished as soon as possible after each training. I hope you realize your wish.