I am 16 years old turning 17 in january. I weigh about 135 lbs and want to gain some muscle before I start Sanda/San Shao kickboxing. I have never worked out in my life and don't have any weights. I have a pull up bar at home and I can also do pushups and situps. My question is how should I work out (types of pushups/situps/pullups and how many times) and also should I work out my legs and how?