Got it working fine just straight. Clicked on 'free license' on the site while logged on my account, then it appeared in ASC, then I activated it, then installed it, then went into Ableton Live 11, checked the plugins button in the tree and in the VST3 folder, I found 'Tape Mello-fi' effect.
I have to mention that today, my ASC was stucked this morning and I uninstalled it, renamed the Arturia folder in %PROGRAMDATA% (on Windows) so settings disappeared, and reinstalled and setup it after downloading from Arturia site. Not that it may haveanything to do with Mello-Fi issues but who knows.
Also, FWIW, I was logged on my account on Arturia site before getting the free license.