Welcome, Kati. The website can be a little confusing, I agree.
You can download the software you require at https://www.claessonedwards.com/download/.
Typically, you install the software configure it and ensure that it all works to your satisfaction. Every option will work, but you get a voiceover inserted in the audio as a “nag” until it i registered.
When ready, there is an option to generate a configuration file which you then send to john@claessonedwards.com and he will generate your licence key. You go to the “register” option and paste the licence data directly into the window, and you are up and running. If you ever change your network MAC address, you will have to apply for a replacement key.