How to capture coordinates of avatar and save it some or pass it?

Hi Everyone!! I am newbie on unity because requirement for a particular project. I have to make a 3D Virtual Environment. In which I have to capture all the collisions in that environment and pass them or just store them. I have to control the avatar/character in that environment and collect every movement of the avatar like motion capturing and communicate to other device/file. From where should I start, guide links and any asset I can use. I have already started learning unity. Kindly help. Thanks Best Regards, Huzaifa