Using the Nuxeo5 scheduler

Hello,

Imagine that I have a method that process data, and I want this method to be
triggered every night to clean up some data.

I can use the scheduler included in Nuxeo 5, but I have some question :

-is the scheduler activated by default when I launch Nuxeo 5
-I don't understand how to fill the "eventId" in the configuration file, I can
imagine that the target is the "method I want to trigger" but how and where can
I define exactly this eventId.

If you have an example it will be great.

Thank you very much.

Damien