Three hours, ten or so people, and one question to sit with. We eat first, because it is easier to be honest with a bowl of something in your hands. Then a long stretch of quiet, and then whatever anyone wants to say.
There is no round of introductions. You do not have to explain what brought you, and you do not have to speak at all. Several people each time come, listen for three hours, and go home, and that is a full and ordinary way to spend the evening.
Come as you are, and leave when you need to leave.
How to join
Write and say you are coming so there is enough food. That is the whole of the process — no ticket, no deposit, nothing to bring.