Your ability to add members to chat rooms depends on the type of room and what permissions the owner granted when it was created.
In public rooms, the room will be listed in Symphony's directory - so anyone can find it to join, and any existing member can add another user.
In private rooms, the creator of the room - the owner - designated the permissions for adding members (ex: only owners can add new members or all can add new users).
For both private and public rooms, the process to add members to a room is the same:
1. From the chat room, click the drop down on the top right corner and select Manage Members if you're a room owner or Members if you are a user. Or, click the count of members just below the room name.
2. In the Chat Participants window, enter the name of the person you want to add in the Add Participants box.
3. Hit Return. Their name will be added to the list of members in the chat room and it will appear on their left navigation.