My client set up html 5 link for me to connect to a remote windows machine from my mac. How do I copy and paste text back and forth please? It does not work currently.
the first part of the answer could be find at the Guacamole documents https://guacamole.apache.org/doc/gug/using-guacamole.html#using-the-clipboard
Then you will see, that pressing Ctrl + Alt + Shift will show you the user menu bar but I can´t tell you where you will find these keys at a MAC.