First time downloading a plug in and it isn't working (or I don't know how to do it)

Hi there,

I recently wanted a way to click a single button so as to get courtesy accidentals to appear throughout my whole score. I was given this reply:

"Courtesy accidentals can be placed by clicking the accidental in the toolbar. If you mean a command to detect places where they should be added and add them all for you in a single click [yes, that's what I wanted], there is a plugin that you can install to do this. See
https://musescore.org/en/project/courtesyaccidentals "

I went there and downloaded it, yet when I went to my piece (V2), clicked on Plugins, I couldn't find the new add courtesy plug in. Going into the folder to which I had sent it in my computer, I tried opening the 'add courtesy naturals' QML file with musescore, but that didn't work either.

Any help?

Thanks