If you have any support on it, call CommVault and get them to help you set it up. If you don't, call them anyway. You might be able to weasel a free setup out of them if you threaten to return it and buy NetBackup. (They don't know you can't return it any more.)

If all that fails, call Dell and get them to help you.

Again, though, it sounds like you got oversold by Dell. There's probably no reason to buy backup software that big if you have a single tape drive. BackupExec or (ugh) ArcServe, as Tony suggested, probably would have worked better for you.