The camera housing included with the NavQPlus mounts to the front "GoPro" style mount on the front plastic:
You must use the screw and bolt that included along with the original camera mount. (This is from the white plastic mount included with the NavQPlus)
The camera flex cable should come out the back of the NavQPlus and loop over top of it. Then route under the lower edge of the front bracket. and up into the camera module. The final setup should look like this:
Screw the front and rear plastic to the top plate using two M3x5 screws from the bottom
The camera flex cable should already be attached to the front plastic.