Restoring WordPress Backups depends mostly on your web hosting provider and what tools they provide and allow to access their database server.
For example many web hosts have phpMyAdmin (web based MySQL DB Admin Tools) built into the web hosting control panel.
Once you know which MySQL DB Admin tool you have available, you simply need to use the ‘restore’ function to import and restore the .sql backup file.
Restoring the File Backups is normally done by FTP. The first step is to extract all of the files from inside of the backup file. The second step is to rename the root directory of your website and create a new empty directory, with the same name. If your website lives at /home/example.com/wordpress/ rename the wordpress/ directory to wordpress_old/ and then create a new (empty) wordpress/ directory. Now if you copy all of the files you extracted from the backup file to the new wordpress/ directory you should end up with an almost identical copy of the wordpress_old/ directory. The wordpress/ directory is the new, restored version, and the wordpress_old/ is the old and broken version. You may need to change some file and directory permissions after a restore, use the old version (in the wordpress_old/ directory) as a guide.
More info can be found on our website here:
https://mywebsiteadvisor.com/learning/software-tutorials/restoring-wordpress-backups/
Please feel free to contact us directly via our website if you have specific questions or get stuck during a restore.
Thank You!