Obtaining coordinates from a calibrated camera

I am doing a computer vision project on object detector (tools) and hand to obtain 2D coordinates.
I have a camera calibrated taking as a pattern a chessboard in which I obtained my camera matrix, distortion parameters, rotation vectors and translation vectors.
The problem is that now I want to use those parameters to be able to project in my plane and know where my objects and hand will be, but having as point (0,0,0) the center of the board. How could I do it?