To do so, just click the `+` next to Chat Rooms in the chat sidebar to see a list of all the public rooms that have been created so far. When you find the one you want to join, click the blue “Join” button. This will add you to the room. The “Join” button will turn grey and show that you're a member of the room. Join a Lync chat room. Open No membership is required (or allowed) to find, enter, post to, or follow an open chat room. Closed Membership is required to enter, post to, or follow a closed chat room; no membership is required to find one. Secret Membership is required to find, enter, post to, or follow a secret chat.