If you have everything connected correctly but can't find any cameras, there is most likely an IP conflict. Both the NVR and IP cameras come with 192.168.1.188 as the default IP. The easiest solution is to is to change the NVR's IP address to something else.
Follow the Initial Setup Guide listed on this page.
If you have Oracle VM VirtualBox installed on Windows, you may find that running a search with the Device Manager may return no results. If you disable the VirtualBox Host-Only Network adapter (find it in Network Settings), that may fix the issue.