How to connect an additional drive to NAS QNAP TS-453Be?

Question

Hard disks

I have a NAS QNAP TS-453Be. Two HDDs are connected to it, now I have physically added one more. All drives are the same - Thoshiba HDWE140, 4TB each. The Storage is configured in some way : Disks are connected in the following way: Two existing disks are somehow combined into a single Storage DataVol1:

I don't understand what raid they are in, and whether they are in a raid at all. As a result, I do not understand how to add another disk to the shared storage to expand its space. Within the Storage, I have a Public folder that stores movies. I need to add additional space there, preferably without losing the files currently stored there:

Answer 1

Surely you will be able to consult by phone/correspondence by email/vk/etc