12 TB with two 6TB drives, how to get MAC to see two drives

GRAID TB 12TB has two 6TB drives. How to get Sierra to see the two drives instead of one. Need to set up RAID1.

is it a G-RAID with Thunderbolt only or does it also have a USB connection on it?

If it is Thunderbolt only then the RAID is handled within Disk Utility since it is a software RAID device.

If it has USB also then it is a hardware RAID device and you need our configurator to change it to RAID1. G-RAID w/Thunderbolt & USB configurator