Adding a physical disk to Centos 6.7

I have an HP DL380 server with 6 72.8GB drives.  I mirrored 2 drives for the system.  I just added the other 4 at RAID 0 for a 288GB data drive.  These drives were created with the on-board hardware array.  The system came up just fine on the mirrored system drive.  How do I find/format/add the 288GB drive that I left for data?  I can't figure it out.  I've been working on Solaris for quite a few years and just can't figure this one out.  It must be something easy.  I did a MINIMAL install on this server so maybe I need to add an application or something.

Any help will be greatly appreciated!
David