I joined a Signal group

[dreamshark]

 My loosely organized neighborhood block club set up a Signal group, so I joined it. It took me a while to even figure out how to do that, as the invitation was sent by email and I read email on my computer, not my phone. Let's just say that it required multiple (non-obvious) steps. But I don't understand how to use it. I saw one announcement of some kind come through on my phone, but I didn't read it carefully and now it has apparently disappeared forever. WTF? 

I find so many supposedly intuitive user interfaces to be incomprehensible. 

On the plus side, Richard and I (especially Richard) were tickled to see that the neighbor had named the group "Halloween Hallway".