I was just curious why the "open games" screen doesn't refresh. Even after joining a game there, it still shows that I'm not joined. Is it just me?

You're correct - this isn't very streamlined. I've actually already done some work in this area that isn't live yet. This will be improved in an upcoming release.

how do you get to the open seat screen (the help page was of no help to me!). I check my "my games" page, but I don't see any open seat games.

If you don't see any, it means there are none. You can always create one!