Add the camera to NVR by Match Code from the NVR:

1). Power on the camera and connect it to the NVR with a network cable.
2). Right click on the monitor screen of that camera channel, choose video manage. 

 

3). Then choose the channel below the added device. On the right corner, click the "match code" option.


4). It will automatically match code and click "OK" to exit.
If it matches code failed, then click "match code" again to make it right.
5). When all cameras are matched codes successfully, unplug network cable from the camera.

You can also use the network cable to connect the camera with the NVR (or router), to make longer distance transmission.