Standard begginer question

Hello everyone, Im 16 years old i weigh 150 and im 6 feet tall and i dont have any body fat , I Play tennis extremly competitevely and im looking at boxing to help with strength training, endurance and tuffness. I know that boxing if anything like tennis involves the proper technique and i am wondering how to start out i am moving to a place with a boxing gym close bye so that could help. Im interested in being competitive with boxing However i am built like a tennis player muscular but im no rocky balboa. Im hoping to bulk up and increase the size of my frame so that i can withstand some punches without getting totally beat down. What do other people here do for training and bulking?