Logging in with @cyphar:cyphar.com works for me. I host my own homeserver so I did have to set it up, but if you are using someone else's homeserver that is all you need to do. The homeserver and identity server information is all provided with the new .well-known/matrix/client support.
if you're not a matrix.org user, you either enter your full mxid to discover your server, or manually enter your homeserver's URL in Advanced. if this isn't working, please yell...