If you just want to copy one card to another card just copy to your pc and then copy to the new card with windows explorer, you don't need anything else.

If you want to combine 2 cards to a new larger card, 'SD Backup' each of them in the Song Manager program, then make a new backup by combining the 2 backups in 'SD Merge', then 'SD Restore' the new combined backup to the new card. This is all in the SD Manage menu of Song Manager.

If you want to just combine selective folders from 2 cards then the simplest is probably the SD Explorer tool.

None of the above will work with audio files, they need to be checked out from Jukebox to the new card. Don't use the SD Explorer tool to backup cards with audio files.