Soundfonts in Musehub to use with musescore 4

I've dragged and dropped a soundfont of thunder, lightning etc from Musehub into my soundfont folder for Musescore 4. However, when I go to mixer I can only access the default MS basic. The soundfont in my folder is a WAV file. I thought Musehub was compatible with musescore 4? Do i need to conver to a .sf2 or .sf3 file? If so, how is this done.
Any help appreciated