On a Windows machine the Computer ID is generated "automatically" (based on the installed hardware, OS version etc, I believe). I honestly do not know how this works with a Mac. I think there are not many Mac users represented in the forum, unfortunately, so I don't know whether anyone is able to answer your question.
Perhaps one of the Apple forums might be able to help you? It is possible that Magix staff might also be able to offer guidance if you have a look at the Support link in the header of any forum page.
One word of advice: do NOT upgrade to OSX Catalina if you do get your installation of SF Pro working. That version of OSX allows only 64 bit apps to run; SF Pro for Mac is 32 bit.