Step 1 : Open the DVR Cover by removing the Screws using an screw driver.
Step 2 : Take the SATA Power Cable and Data Cable.
If you have confusion ,its simple the Blue cable in the picture is SATA Data cable and other one is SATA Power cable.
Step 3 : Connect the SATA Cable to DVR and Hard Disk.
Connect the Cables to its respective slots.
You are Done.