In case you don't already have the application installed on your PC, download it from its official page, then double-click the file and follow the steps to complete the setup process. Now, run The Complete Genealogy Reporter, press the Register button from the bar on the upper side of the window and then click the second button, the one that looks like a receipt leading to a PC. (If you hover the mouse cursor over it, it will say Enter Registration Code.) Finally, enter registered name, then the registration code, press then green checkmark button and you're done.
If you require additional assistance, the application's developers can be contacted using this email address: firstname.lastname@example.org