The backup you can download from the PBN dashboard is not a special backup. It's just an archive that contains your website files and a database file (.sql). Also, because of that, there are no specific ways to restore it.
All you need to do is go to cPanel > File Manager (or use FTP) and upload your website's files to your domain's root folder.
If you are trying to restore the database file, just go to cPanel > phpMyAdmin and restore it there. If you deleted the database, then you will need to recreate it in cPanel. Don't forget to recreate your database's user as well.