Call distribution is determined based on following criteria (in order):

1. Agent-Availability 

If the Agent is Logged in and the status is set on 'Available'; And, the agent is not on a call with client; And, the agent has surpassed wrap-up duration.

2. Call-Group Strategy

Calls are routed based on the strategy set in the 'Call-Groups' tab. Most common criteria for distinguishing between the call groups you set up are region & department.