You can use a status/emoji icon to indicate to others that your are away, happy, raising your hand, and other changes in status.
To set a status, select the Users List Toggle  to expand the users list panel and public chat. Select your User Icon  in the users list (it will always be at the top).
Choose Set a Status  - A pop-up menu will appear giving you the available emojis or status icons from the Status List . If you do not want to set a status, select Back  to return to the users list.
When you choose a status emoji it will appear in the center of your User Icon in the users list. For others, your user icon will also move to the top of the users list until your has been cleared.
You can clear your status by re-selecting your name in the Users list then selecting Clear Status.
Note: a moderator can also clear your status.