Musescore 4 instruments

Hi, I have a problem with musescore 4.
In musescore 3 I could change the instrument sound only by clicking on mixer and changing it.
In musescore 4 I can change/add the instruments I want, but I can't change their sound.
How can I get, for example, bright grand piano? Or Honky Tonk piano?
Pls help me,
thank you :D