Communication between ground reach and mobile reach

I would like to use the reach kit with Pixhawk on board of a drone, with a ground station reach in order to minimize the deviations.
How do the two stations communicate with each other and with the pixhawk in order to fix the mistakes?
Can someone tell me how to i set up the system of these 3 components (pixhawk,mobile reach, stationary reach)?

Thanks in advance,

Hi Roi,

Look at these docs.
If you still have questions after that, please write here.