Hi there! Well first you need to start reading here about it
http://www.joomlaplug.com/Tools/JoomlaPlug_Tools/JCron_Scheduler.html
Basically you have to do 2 things:
- first go in JCron Config area and try to enable it(click the green button)
- second, go in the manage cron area and click on add a new cron
On that page you have 2 options for a cron job type, execute the cron by adding a link or by adding a shell command! I would suggest to first try the shell command(exmaple: "php /home/.../administrator/components/com_cloner/cloner.cron.php"

, also check the checkboxes from below the page so the cronjob gets logged when executed!
Some more info about cron jobs and how they works is here
http://en.wikipedia.org/wiki/Cron
Let me know if you have further questions, and tell me where exactly are you stuck with the component?
Regards! Ovidiu