There are many tutorials that show how to use SoundFonts on GarageBand. (Source)
However, when I do step 5 on this page, no dropdown menu appears (and nothing happens).
How can I install SoundFonts to GarageBand 10.2?
Ah yes, this is something Apple's been sent feedback about in terms of their user interface design for GarageBand 10. It's actually a quick fix that will hopefully get addressed in an upcoming update (changing the default setting on installation will probably do the trick for most people).
Using SoundFont (SF2) files in GarageBand v10
To get your SoundFont files to work in GarageBand 10, follow these steps:
Now you can play the sounds from the SoundFont (SF2) file you selected.
Installing SoundFont files on macOS
The steps above show how to use SoundFont files within GarageBand 10. However, if you want to download/install additional SoundFont files in macOS to make them available to GarageBand and other apps, follow these steps:
Now your SoundFont files will be available to any apps that support them.
now it uses the soundfont good luck i hoped this worked for you