Before you can use any algorithm that involves departments you must do three things:
You can enable departments by going to Tickets->Settings->General. About 1/3 of the way down the page you’ll see a checkbox labeled Enable departments management. You should check that box and then click the Save button.
Once departments are enabled you can create a list of departments that match your situation. Navigate to Tickets->Departments and add your departments there.
To assign support agents to departments you must do so in the support agent’s user profile. Access the agent’s user profile by going to the USERS menu option in the left hand side of the WordPress Administration Console.
Once you are inside agent’s profile, scroll down to the section with the heading: Awesome Support Preferences
Check off the department(s) that the agent is allowed to work in and then click the Save button at the bottom of the page.