adding more music fonts

Hi
I'd like to know how or where new music fonts (opentypes), such as 'NoteSans', 'Bravura' or 'Maestro', could be added or installed to be used as MuseScore styles... or if it is possible at all (...?)
I tried searching for the default font files (Elementaller, Bravura & Gonville) in some subfolder within the MuseScore installation folder to see if new font files could be copied and pasted there so they could afterwards appear in the styles window... but with no success :( so i figured out that's not the way

Thanks beforehand :)