Possible to have Hikvision NVR and 6 cams offline? No router?

Hey all - I have six cams that ran through two PoE switches and finally to an old PC with zero internet connection. All was fine until the HDD crashed in the PC! I bought a Hik 7608 NVR and plugged the network cable into it (not one of the POE ports) but it wasn't able to find any cameras, and same thing when I plugged the network cable into one of the POE ports.

I've just read that this NVR likes 192.168.254 addresses, and my cams are all 192.168.0 - sounds like I should used SADP to...

Possible to have Hikvision NVR and 6 cams offline? No router?