In fact, I think shoulder muscles are more worth practicing, because they can improve your explosive power. Another point is that biceps brachii makes your arms more beautiful. If you really want to practice, use it with creatine and protein powder. If you have the conditions, you can go to the gym to become a member or something, and then let the coach teach you how to practice in the gym, which can improve your muscles in an all-round way. If you become a member, you should keep practicing every day.