Does it have any data on it already? Some of the external enclosures perform some weird LBA shenanigans so that the full capacity can be used. If that's the case, you'll need to copy the data from the drive, shuck it, repartition/format then copy your data back.
If it's empty, then I think it should be pretty straight forward. (assuming the case is easy to open)
RAID protection is only for failed drives. That's it. It's no replacement for a proper backup.