1、Install BackUpWordPress either via the WordPress.org plugin directory, or by uploading the files to your server.
2、Activate the plugin.
3、Sit back and relax safe in the knowledge that your whole site will be backed up every day.
The plugin will try to use the mysqldump and zip commands via shell if they are available, using these will greatly improve the time it takes to back up your site. If you know about such things then you can point the plugin in the right direction by defining HMBKP_ZIP_PATH and HMBKP_MYSQLDUMP_PATH in your wp-config.php.