You will need to know either the RTSP URI for the camera, or the 'ONVIF port.
If neither are mentioned in the camera user manual, and the camera is ONVIF compatible, you can get both (and lots more) using the very good Windows open-source tool 'ONVIF Device Manager' from sourceforge.net
The ONVIF port (which you'd use as the Management Port if you configure the NVR channel with the ONVIF protocol) is shown at the bottom of the 'Identification' page, after the ':' after the camera IP address. If there is no ':', the ONVIF port=80
The RTSP URI is shown at the bottom of the 'Live Video' page.
And you will need to assign the camera an IP address to match the range used by your NVR PoE ports - typically 192.168.254.2 and up.
A nice feature of the Hikvision NVR is the ability to define 'custom protocols' which can be configured for each non-Hik camera you may want to add.
Here is an example for an 'IP Cloud Camera model IPCC-B10', a 720P low-cost Chinese camera. It also works just fine with an ONVIF choice.