Mobius 5-Bay set up in RAID 5. One hard drive failed and it is beeping. I bought a new hard drive. How may I replace it?

Eject the Mobius and power it off. Remove the failed drive that was indicated by the Red LED. Insert the new drive. Power on the Mobius. After a few moments, the light will blink consistently about 2-3 times per second. This indicates a rebuild in progress. You may also monitor the rebuild status by downloading the optional RAID Manager utility found under the Resources tab of the Mobius RAID page.