Gunn3y
Head-Fier
Correct me if I’m wrong, but I think that’s a free trial of Parallels rather than Windows. It’ll still require a Windows licence.
The top part of the page mentions the free Parallels trial, but each of the “Methods” sections underneath that walks you through ways to use an unlicensed copy of Windows to trial. Also ignoring the article I have run Windows un-activated many times in Parallels, so it’s definitely possible.