Connect your PC Ethernet cable to a spare PoE port on the NVR. You don't need to change the PC IP address.
Used SADP to find the missing cameras and set their IP address to that of the PoE port that they are connected to.
At that point - the cameras should be visible in Live View, and available to configure.
the seller tech was able to help me out. I didn't expect buying it from china would get this kind of service but the walked though me step by step which was great.
What you said did the trick but I wouldn't understand it because it doesn't make sense to me and until the tech did it.
1) Connect the main lan port from nvr to the router.
2) Connect ethernet to camera and to nvr poe port
3) Connect another ethernet to the nvr poe port and to router (this will allow the nvr to detect the camera and it will not detect it if you don't do this)
4) open SADP (it's a software that comes with your camera or you can download it) to change the IP
5) Change the camera IP Address to 192.168.254.xx
6) Change the IPv4 Gateway to 192.168.254.x (or something else but has 254 after the last digit)