Place the RPI Camera inside the case, the case inside the tilt arm and then on the bed mount. You must place the mount not on the heated bed itself but on the bottom aluminium tray. The mount is thin enough to not hit the printer parts at the bottom.
I designed it with front installation in mind, that's the reason fot the extra-long horizontal mount. After that I changed to back installation and a shorter mount will work too and will have less vibrations, so stay tuned for version 2.
Tip: if you have a v2 camera you should thin a bit the inner edge of the back camera case, you can see two small black dots in one picture.