Why can't I see my cameras on SADP but I can see my NVR?
If the cameras are plugged into the PoE switch on the back of the recorder, they are technically held within their own private network. If you are trying to access the cameras on the back of the NVR, you will need to plug your computer into the back of the NVR, using one of the PoE ports intended for the cameras; this will allow your computer (and SADP) to talk to the cameras.
If your computer does not have a LAN port for ethernet, you may also use an ethernet cable to plug from the back of the NVR into your router, revealing the cameras to your main network. Once they are able to be seen on the network, you should be able to see the cameras using the SADP tool.