Where can I find documentation on how to implement a dispatch event using webhooks?

I am in the same position with you. The only thing I found useful is this: https://www.tothenew.com/blog/unleashing-real-time-connections-a-compreh...

Here it says something about defining the payload.
But I can't find anything like that (e.g. a field Payload) that can help for this.

Is there anybody that could guide us on how to use this module?

How do you define the payload? And Where?