To restore a backup on Joomla, follow these steps:
1. Log in to your Joomla backend.
2. Go to Extensions > Manage > Install.
3. Choose the “Upload Package File” tab and select the backup file.
4. Click “Upload & Install”.
5. Once the installation is complete, go to Extensions > Manage > Manage.
6. Check the box next to the backup extension and click the “Restore” button.
7. Follow the prompts to complete the restoration process.
Note: Make sure to backup your current version of Joomla before restoring a backup, as restoring can overwrite your current files and database.