Before an operator is able to go online and begin accepting chat requests, the setup admin will need to assign the operator to a department.  To assign an operator to a department, login to the PHP Live! setup area (example: www.YourSite.com/phplive/setup) and click the "Operators" to navigation menu.  At this page, click the "Assign Operators to Department" sub menu and assign the operator to a department.  Once this has been done, you should see the operator to department assignment on the right side of the page.