When your clients join a session, you will see a pop-up and hear a sound. If you are not ready to join them, you can text chat with them. The chat box will also give you a link to move to the session with them. This is great if you have clients/students back-to-back.
If a person joins by your personal Join-by-LINK, you will be notified also and can approve or deny their request. If they join before you login, their request will pop up when you login.