You can register BladePro online via credit card using the Kagi Online Order Processing service.
Alternatively, you can use the "Register" application that came with Blade to create a customized form, which you then send to Kagi, whose address is given on the form. Several different means of payment are supported.
After Kagi processes your payment, which takes a few days, they e-mail you the registration code in a message with the subject "Thanks for your payment". If you don't have e-mail, you will get the code on a postcard instead.
Lastly, click the "register" button inside the BladePro filter, and type in your code.
The latest updates are available on the Blade page.
Although Kagi cannot provide technical support for the software, the author is more than willing to answer questions.