How to mount an external hard drive on ownCloud 10.0.4 (Stable)?

Good morning!
I can not mount my external hard drive in ownCloud 10.0.4 Stable. The external hard drive is a 500GB Hitachi. Using ownCloud Server 10.0.4 Stable on Raspberry Pi 2 Model B. What can I do? And how?

Hi, have you tried this?

No, how can I do? ssh don't work. Can I do this command by os terminal?

OS Terminal = you are on the system and can type in commands?

Then type in the occ commands for mounting drives