Inverse kinematics for R6?

I'm developing a game and my team have recently done most of the needed work and the last thing needed for the game is animations, my friend did the animations but I am not sure about the side-to-side walking animations also known as inverse kinematics. So far I have only seen R15 and I'm not sure about how it works for R6.If you have any idea of how it works please tell me.