In the Attendees pod (usually appearing on the left in most meeting layouts), hover over the name of the person to whom you'd like to send a private chat. A pop-up will appear, as shown below. Click on the words "Start Private Chat." You will see a new tab appear next to the "everyone" chat tab. Type your message in the private chat and be sure to click back on the everyone tab if you want to type to the entire class again. This private chat is primarily to be used for troubleshooting with a support person during a live meeting.