How do you edit or delete a Message from Messages?

[#1]

As usual, Support is of no help whatsoever.  So I'm asking here.  When you've put a message in Messages and you've changed your mind about it, how do you go about Deleting the thing?  Since they changed the Messages utility, I can't find the way to either Edit or Delete a message.  So how are things Edited and Deleted in Messages now?  

[#2]

When you hover over a message, you should see 3 green dots. Click that, and you should be able to delete, but quickly, because unless they changed things, I think they're not deletable after a certain length of time.

[#3]

I no longer see any 3 dots for option to edit or delete messages. Whats going on?