While inside of a ROOM venue, if you want to chat with other participants, simply click on the "Open Chat" icon at the screen's bottom right.
This detail of the in-meeting tool tray shows the Open Chat as the first among the icons clustered to the right, providing optimal access, now that it is not embedded in a sub-menu.
When selected it will open a chat window at the user's screen right (a shared chat thread for all guests), where you'll also be able to share links and files through the course of the meeting.
And, of course, it wouldn't be complete without an army of eager emojis waiting for the next round of emo-feedback!
Both attachments and links can easily be shared at will.
To learn more about ROOM's in-meeting tool tray's features, please refer to the following:
Finding Your Way Around (Interaction, Navigation & Tools)