The info is in the user guide here: [URL] In chapter 4 under 'Cartridge magazines' describes the bulk load of tapes, then in chapter 5 look for import and export of media.
To my greatest surprise, I'm unable to find a guide on how to add cartridges in a TL2000 PowerVault magazine. (Yes, yes, I checked the manual but can't find it there either.) Could somebody please guide me through the process or link to an how to guide? It must be simple, right? Yours blushingly, /Jack 
TL2000 Add cartridge How-To