You must have Java turned on in your browser. When you click on Chat, a new window will open in a little while, and it will take you to a chat room. You can look at the other rooms and change to whatever room you want. It involves typing your message in a small window at the bottom, then clicking Send or hitting the Return key on your keyboard. Messages from a number of people appear in the large window -- and for me at least it can be hard to follow what all the people are saying, if there are a lot of them in chat at one time.