You can also follow this video to remove the old hard drive from your DVR.
Installation Steps:
1. Loosen the five screws securing the DVR cover.
2. Push the cover forward and remove it.
3. Connect the hard drive to the DVR system.
4. Power on the DVR and check if the hard drive is detected. Then power off the system again. Note: The interface may vary slightly depending on the model.
5. Secure the hard drive inside the DVR using the provided screws.