Backup Level
This defines what type of backup to perform. There are two options:
  1. Full Backup: Backup all files.
  2. Incremental Backup: Only backup files which have changed since the last Full Backup.

Please note that this option only has an effect if you have chosed a Backup Schedule for this named backup. If the schedule is set to "Never" then this option is never used.

Also note that you cannot do an incremental backup unless you already have a full backup done. If you are setting this named backup to "Incremental" then be sure to do a full one by hand.