Here's how to invite others to a room:
From inside the room, click on the SHARE button in the top right of the screen.
Add the email address of the persons you want to invite in the pop-up window to send an in app notification, OR you can copy the invitation link and paste into an email.
Remember: users invited to a room can see all current and future murals in that room.
Now you'll be able to get your whole team into the same project a whole lot faster!