in order to get muscular you have to train your muscles. you can do this by
* body weight training
when you train, your muscles contract in order to lift weights and so on. by doing this your muscles get tired. this will cause you to get small cuts on your muscle which will get repaired in time.when your muscle gets repaired you will also get a little bit more mass then it had on each cut. in order to increase this amount of muscle gains you have to get alot of protein . in order to get muscle you have to get high amount of protein each day. the rule is:
you have to get 1.5 to 2 grams of protein for each kilo of your lean body mass ( muscle mass)
also you shouldn’t get any more than 25 grams of protein in one hour. this is number is depended on your tolerance. otherwise your body wont fully take benefits of the protein.