Provided you have permission, you'll want to press the blue chat button at the top centre of the window to create a new group chat.
Select the users from the left hand side of the screen and name the group chat in the center of your screen.
You'll then be able to chat with everyone in the group.
If you need any further help today, please don't hesitate to contact our friendly support team on 0330 122 6000 or by email!