Click the three-dot menu in the top right of a chat to access Chat details and view room information, room members and toggle chat room settings as the owner (figure 1):
Figure 1 Open chat details
Click Customize to add a chat room alias, assign a color, sounds, or adjust notifications (figure 2):
Figure 2 Customize chat
Click Members to view or add room members and, as room owner, promote, demote, or remove members (figure 3):
Figure 3 View members list
Click on Attachments to see all file attachments shared in this room (figure 4):
Figure 4 View all attachments
Note: Your view of chat details depends on your role in that room and whether or not files have been shared