Inherited a My Cloud Mirror from deceased relative; how do I access/format/use it?

Hi there, first post here!

It’s all in the title; I’ve got at 12Tb My Cloud Mirror but I have no idea how to access it.

I’ve tried hooking it up to my router and going to My Cloud, but the host just doesn’t resolve and I’m left hanging.

I’d be happy to format it (I actually wanna sell it), but before I do so I just want to check what’s on the drive, as there might be some media that could be precious to my family.

Any and all advice welcome, thanks!

EDIT: Will updating the firmware per this link help? Upgrade My Cloud OS 3 Firmware to My Cloud OS 5

Ah! I’ve done the reset, maybe it was the IP address I was missing; will check in on the router.

Thanks for the tip, friend!