The first two steps in creating a Cost Report start by making sure your Revenue Sharing is correct...
Clients > Client's Active Account > Revenue Sharing > Edit
and that an appropriate Cost Profile has been created. Once both have been completed, go to the Cost Reports tab and click the '+ADD REPORT' button in the top right corner.
Name the report, choose what policy the report will pull information from, and select the appropriate cost profiles. Please note, you can add new cost profiles from this screen as well. Once done, click 'Save & Download Report' at the bottom of the screen and the report will begin download to your computer.