1. Go to this page and download the library: Download litvinab/cron-event library. Choose the download type require.
2. Extract the ZIP file and open the index.php.
3. Add this code to the index.php.
<?php
require_once('vendor/autoload.php');
/* Start to develop here. Best regards https://php-download.com/ */
// get cron manager
$cronManager = $this->get('cron_event.manager');
// set timer with: human name, name, period
// name of the symfony event: `cron_event.` + name
$timer = $cronManager->setTimer('My timer', 'test_timer', 60);