Can't use the FMSE despite having the licence

So, i downloaded fmse19 , it was a zip file with one malicense file and one setup , I ran the setup and opened the editor , loaded the game and when i tried to change the values it says you need to be registered, I researched for a bit , got to know , it was discontinued and the author gave free license for all the previous version , but I don't know how to use that license the editor just won't detect it , I searched here and there made files , and all
It is just not working at all man , someone help
How do I use it