To use Cron you don't need the library, it's all very simple - crowns at a certain time to do something, anything. In your case it needs to launch your script or group of scripts. You just need to properly arrange the logic in a console controller.
As an example, the entry in Crontab-e looks like this:
> */5 * * * * / usr/bin/php /home/www/project/path/to/script.php --some=param
The whole logic of the script, of course, on you.
But Kron is very limited, not suitable for something complicated and special, or when task a whole lot about they are very heavy. There are more, and wrote other commentators, brokers queues - RabbitMQ, Gearman and others. These things can run tasks in the background, outside the main workflow. Based on them are built such wonderful things as CommandBus. But it is at times difficult chart.