If your disks all say Basic then you either don't have any RAID arrays configured or you are using a hardware RAID.
If you are using a software RAID you'll see the word Dynamic and each drive letter will be the same on multiple drives.
Your other option for checking this is:
If you see drives that have a manufacturer and model number in the name then the RAID is not configured.
If you see drives named like that have a RAID manufacturer name or have words like "Virtual Disk" or "SCSI Disk Device" you have successfully configured your RAID.