After installing you have to open a page and then it will initiate a second 3-step installation. Did you see that?
Once that is done you can access any of the functionality from the Server Behaviors panel. The first time you open an interface it will ask for the serial.
If you didn't see the secondary installer in Dreamweaver, please try reinstalling the extension and open a page after restarting Dreamweaver and wait for the three steps to complete, that should correct the problem.