I used to be thin, too From the third year of high school, I go home every day, do push-ups before taking a shower, then take a shower, eat and have classes at night. When I went to college, the whole person changed!

First, exercise the chest muscles and biceps brachii, and do push-ups. Do 3 groups every day, with 25 in each group.

Exercise abdominal muscles, sit-ups, 3 groups, 25 in each group.

Exercise your back to make it strong and do pull-ups, 3 groups a day, also a group of 25.

Keep doing it every day, don't overdo it, but keep doing it. You'd better exercise before taking a bath.

I wish you good muscles.