Ghost Notes on Drums

First step - be sure to update, that version is years old now. The current AppImage is the version we support, and it is always available on this site.

Next, regarding ghost notes - there is no specific "ghost note" sound in the General MIDI standard, so the default soundfont doesn't have such a sound. But you can install third-party soundfonts that might include non-standard sounds. See the Handbook section on soundfonts for more info.

See:
https://musescore.org/en/node/298624#comment-966654
where an example is attached. Check the velocity setting of the ghost notes in the Inspector.