Adding Reversing Camera to 2015 CX-5

I'm looking for some advice on how easy it is to add a reversing camera to my 2015 CX 5.
I'm currently replacing the tailgate due to a reversing incident (2nd one!) and found one at a scrap yard that's the right colour. But, it looks like the scrap one has a camera included which mine currently doesn't...
Does anyone know what I have to do to integrate the camera into the existing system? Presumably the wiring loom to the tailgate is the same, so will it just work or will I need some messing about with the head unit or other wiring?
I don't know about the CX5 wiring for a rear camera. However, I did add a rear camera to my 2018 MX5. It needed to be wired into the head unit of the information system with wiring running to the rear trunk to the new camera. There was no pre-exiting wiring. For the MX5 you can buy an OEM or an aftermarket kit that provide the connector for the info system, camera, and wiring. I don't know if such a kit is available for your MY CX5.
I added one to my 2013 when I upgraded the stereo. And yeah, has to run a wire. It wasn't very hard at all though. Worst part was fishing the wire through the rubber boot. Wire "goo" made it a lot easier.
If possible, try to find a wiring diagram for '15 CX-5. (a paper book o PDF format)
Your answer should be in it.