So I got some basic information which already might help you. First of all I’d recommend to run a local test instance in development mode (default) because the websocket server will then log everything that is send and received additionally to processing information.
However, after a websocket connection is established (on /ws or port 6042, depending on your setup) various events are send end received. For each of those events a backend module exists which processes it. The names should be pretty self explaining in the domain of Zammad - if not let me know.
I think the most interesting one for you right now is the login event which takes a HTTP session (id) and upgrades/authenticates your WS connection.
Let me know if you got thinks working and what your next questions are.