Hello,
To enable the ability for the operator to initiate a chat with a visitor, you should check out "Settings -> Optional Services -> Enable Tracking and Inviting". Once this option is enabled you should also generate a new button. Once this new button is placed on your site you should see a new "Visitors on site" section on the visitors page. From there you can invite visitors to start chatting with you.
You can search the forum again to see if there is any more information that you can get about this feature.