No worries, glad to help.
Since you say you have not added anything to the NAS yet, I recommend redoing your drives as RAID-5 using all four disks. This allows one disk to fail and the array can still function while you get a replacement drive.
Backing up to the same NAS is not recommended. If the NAS fails or has firmware problems after an update, it takes out your backup as well. Better to buy an external USB hard disk, attach it to your PC from time to time and backup to that instead.
When you change from your current dual RAID-1 setup to a single RAID-5 setup, you will lose ALL your data on the NAS. Be aware of that.
When you are ready, go ahead and Modify/recreate your setup as RAID-5. Then sent us a screenshot of the drives like before, so we can confirm it.
While you’re doing that, visit here:
PLEX allows you to host a home media server on your NAS. And you can access it from outside your house too. And they have a cool iPad/iPhone/Android app to locally or remotely access your music:
PLEX is another topic, of course.
Note that PLEX is free. But, if you want to access it from outside your house or do movie transcoding, you’ll need to buy a PLEX Pass. Like most people I bought the Lifetime PLEX Pass for $120.
Anyway, let’s get your RAID-5 going!