Your best option is probably to first explore your current hosting environment for the possibilities of Cronjobs. It might be called “Scheduled Tasks” or similar.
Alternatively you can schedule a task from within WordPress via wp_schedule_event() (though if you’re using the default WP Cron, you can’t be certain of it running at the specified time) and load that file via
require WP_CONTENT_DIR . '/plugins/modern-events-calendar/app/crons/g-export.php';