The most common way is to add an external hard drive that is compatible with your DVR system. Here’s how to use it: Use an eSATA cable to connect the external hard drive. Navigate to the SATA port at the back of the DVR and the back of the external hard drive. Plug the eSATA cable into the SATA port of the DVR and the other end into the SATA port of the external hard drive. Plug the DVR into a power outlet and turn on it. Once reboots, it will automatically detect the external hard drive.