Boxing Fighting Game

I am newbie to corona, i wants to make a boxing fighting game. I am not getting the correct way how, i can make it. i have player one and two, i am using sprite animation for there fighting position. I have defined both as dynamic physical bodies so that if, the colloid i can get it. But how to make them fight.

I am not getting the right path can any body suggest me how i can achieve this in corona.