0. Login as root (Seeing a pattern yet?)
1. Identify the drive.
df -h and take note of the entries.
By the process of elimination, the one in the list in /dev/ that is not part of the df -h listing is the culprit.
2. Create the filesystem
/sbin/mkfs -t ext3 /dev/xxx where xxx is the drive identified in Step 1.
3. Mount the filesystem
mount -t ext3 /dev/xxx /mnt/myfoldername where my folder name is - you guessed it!
4. Check to make sure it is there!