Take a look into the script, the restore procedure is described in the comments at the beginning of the script:
# Restore part -============================
# Restore is meant to be little interactive, the messages are on standard output
# Dir's are restored verbose with tar by default.
# Last minute of the day "$hm" is set to 2359 but the backup is started at 03:40
# so this should be set AFTER the backup has ended! At 23:59 of the backup day
# we can have many files modified from the 03:40. The not so perfect solution is
# to backup later in the day (23:00) and hope the backup finishes until 23:59
# My server is still loaded on the 23:00, so I use 03:40 in cron and hm=2359
# because a full backup last for more than 16 hours for tar.bz2
# For sure I will loose all files created between 03:40 and 23:59 of that day.
# To prevent that I can restore files one day AFTER the day I want to restore
# and use find --newer to delete unwanted files.
# To restore dirs make sure you have the full backup from that month and use:
# `back-res dir /etc 2009-11-23 /`
# to restore the "/etc" dir from date 2009-11-23 to root
# `back-res dir /etc 2009-11-23 /tmp` is used to restore the "/etc" dir to /tmp
# `back-res dir all 2009-11-23 /`
# to restore all directories from date 2009-11-23 to root
# To restore databases use:
# `back-res db mysql 2009-11-23`
# to restore the "mysql" database from date 2009-11-23 to local mysql server
# `back-res db all 2009-11-23`
# to restore all databases from date 2009-11-23 to local mysql server