In the Backup to section, you can s

In the Backup to section, you can select File or tape device if you want to save to a file on the same system. In the adjacent field, either enter a path like /backup/myfiles.tar, or if you have an attached tape drive use a path like /dev/st0 (the first SCSI tape drive).
Alternately, you can select the Host option, and enter a remote hostname, login name and remote file into the three fields next to it. Remote backups are clearly preferable in most cases, as they can be restored if the system being backed up completely dies!