To add a recording device in NVMS-1000 for Windows, you need to go to the "Device" tab and click on "Add DVR/NVR". Then you need to fill out the device information and click on "Add". Once the device is added, you will be able to view playbacks along with the live preview. If you are still having trouble adding the device, you can refer to the NVMS-1000 user manual or contact technical support.