Pxhawk 4+ 2 Rpi3 + picamera v2

Hi Everyone im trying to do a drone project with a pixhawk 4 and 2 raspberry pi 3 to make drone that can track motion with the picamera v2 im have tried a lot off tutorial but o think they nedds updates and im didint find ways on how to make the real connection between bords yet if there is any updates of 2018 about this connections let me know please the time is Running and im blocked kimd of need some help