If you want to start from scratch, follow the steps below:
Power off the box and pull all the hard drives out. Power on the box and log in to web UI. Insert each HDDs one at a time while the system is running, and wait for the disk LED to illuminate. Scan for new drives and configure RAID.
Btw, if you FW version is below 1.4, it's highly recommended that you upgrade to 1.4: https://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&DwnldID=16833. Follow the steps in the release notes strictly to complete the upgrade.