How to initialize the Extend Volume on NAS Drive

I have the 4TB My Book NAS drive. How do I recognize the Extend Volume? It’s set to JBOD but how do i get to that volume or initialize it if need be?

Once you set the JBOD the main volume and the extended volume will be kep as separate devices with separate names.

How do I get to that second drive?

For the data volume, I can just type \\public\

How do I get to the extend volume. 

By default the extended (Second) volume is empty and has no shares, so you’ll have to create one share on the extended volume first so you can use it. So go to the configuration page> log in> go to ADV mode> Storage> Folder Shares>  Create any new share you want and it will now give you the option to create it in the extended volume.