How to track buttons and other customized events.using JS tracker

Hi -

I am new in snowplow, i am starting with stdout output to log data as a first step, and later i will use kafka real-time if the tracking goes well :slight_smile: .
My issue is how to track buttons and try to filter them like in the customFormTracking.
Finally i am a little confused about how to set custumized events, i read the unstructedEvents documentation and still donโ€™t understand how to set self describing JSON and my own Iglu repo.