you can install (Mozilla Firefox) Browser it's best then (Internet Explorer) , and you will find chat window in below of the page it's so easy and flexible to use it ;)

Hi! You mean italki window? Go on the top of the italki window, where it says 'chat on/off' (Click on 'chat on', of course). Then, on the bottom, you'll see a bar which contacts are online and able to chat with them. Click there, and then on the contacts picture.