At the bottom of your screen, you can see two white windows. The top one is the “incoming chat”.
It will show you general messages from other people as well as messages to you.
The one at the bottom is the “outgoing chat” where you type your words, when ready to send use the return key.
First you type your message in the lower of the two chat bars
Then you press the enter key on your key board or press TALK at the right (make sure your message goes to the Table - otherwise use the scroll bar at the far right)
and your message will show in the bigger chat bar. See below picture
Click HERE to find out how to change the text size in the chat bar.