Definitely Read my guide on Backup WP via Crontab Script
Download this Restore-Wordpress-Website-from-TAR-and-SQL-dump.txt.
#Restore WordPress Website from TAR and SQL dump
1. IMO you should delete the directory of your WordPress install if exists (make backup first) and then just unpack tar file and place it where it used to be!
2. The SQL file needs to be imported back into MySQL
If database exists remove it via:
*This assumes you followed my Backup Guide and created .sqlpwd file*
OR if on new system or don't have .sqlpwd file use:
--Apache must be configured the same as before, or other changes must be made, but that is beyond the scope of this guide.
I recommend practicing a full restore in a Virtual Box so you aren't doing it your first time when its mission critical time!