Download The SiX Call Center
Download the SiXCTI CallCenter_v3 Call Center. This will download a zip file with the xml representation of the Call Center. Unzip the file once downloaded.
Import The Call Center
From the Setup Menu, navigate to Feature Settings->Service->Call Center->Call Center.
Select the Import button.
Select the file that was downloaded in step 1.
Assign Users To Call Center
Once the Call Center is imported, you can assign users to the Call Center for use.