The Join/Leave queue button is a custom button that can be deployed to Yealink phones. It allows you to join and leave a call queue or hunt group through one button. Your status (available or unavailable) is also shown on the button by using the red and green lights, as well as a temporary message shown on the wallpaper.
This is a custom feature that must be configured by celito. Please contact support if you need this feature enabled. The actual text, button name, and other slight details for your button may vary from what is shown here.
OK
You will hear an audio prompt telling you that you are now available or unavailable, depending on which option you selected.