Setting up this DAS is a piece of cake, and I am sure even novice users won't face any issues as long as they take a look at the product manual first, or read through this review. For starters, you have to install the disks on the trays. The next step is to connect power and the provided Thunderbolt 3 cable to both the DAS and the client system. The final step, for the moment, is to power on the DAS and wait for it to boot.
From the factory, the small screw at the back is set to the Single Disk configuration, so if you plan to use two drives, this has to be changed. With the provided small screwdriver, rotate the switch until the pointer shows the desired RAID type. Once the RAID selection is made, use the included reset pin (not a thimble as TerraMaster writes in the product manual) to press and hold the reset button until the newly set RAID configuration takes effect. While you hold the reset button, pay attention to the front LED indicators. Once these turn from red to green, the RAID array is ready. Lastly, you have to format your new storage to be able to use it.
If your device is in RAID 1 mode and one of the drives goes bad, you can replace it with another good one without losing any data. As TerraMaster states, the device must remain powered on and connected to the computer when installing the new drive. During data recovery, the device and, consequently, connected system need to remain powered on. During the recovery, the new disk's indicator will flash orange until the procedure finishes, which has it turn green.
I should remind you that RAID 1, or any of the higher RAID levels, do not provide enough protection for your data. The best solution is to keep as many copies of your sensitive data as possible, either on the cloud or other storage devices, or. even better, optical drives (which are almost extinct now).