Buy Workflow Scheduler license for each web front-end server.
Download Hardware ID Generator. You can find download link in the e-mail message with order number from our online store. Run it on all WFE-servers of your farm. Copy generated keys and send them to firstname.lastname@example.org with your order number in the subject.
We will generate licenses for you and will send them to your e-mail within one day.
Place received *.license files in the root folder of all Sharepoint web-applications on WFE-servers according to generated keys. If you use port 80 it is usually here: c:\inetpub\wwwroot\wss\VirtualDirectories\80\