Hi Pierre,
thanks for using BackWPup. Currently BackWPup does not provide a restore feature. We plan to implement taht feature into a future release of BackWPup Pro.
Generally speaking, you need to restore a) your files and/or b) your database.
Restoring your files is easy: unpack your file backup and upload its contents to the appropriate location on your server via FTP.
In order to restore the tables of a database, you’d need a access to your database via a tool like phpMyAdmin. Just google restore wordpress database phpmyadmin and you’ll find a bunch of tutorials. Maybe set your Google search setting to last year to be sure the info is valid. The WordPress Codex has a quick tutorial as well: http://codex.ww.wp.xz.cn/Restoring_Your_Database_From_Backup
