Event Correlation using own event

I have was navigating around graylog alert part. And I saw a Event correlation rule, it only accept some event inside illuminate.

Can I create my own event to to put inside the event to do a correlation?

Yes, any active event can be chosen to use in a correlation event.

Yea I have found out how to do it.

Needed to add a Filter & Aggregation before we able able to add into the event correlation.

Thanks for your reply.