Press F5 when you open Scumm
Go to the launcher, options
Go to Audio, change Preferred Device to Fluidsynth
Then, go to MIDI and change the GM device to Fluidsynth
Next, you are ready to plug in a soundfont of your choice
Do that, save and launch sam and max, it should work!

thank you for reading my first guide on steam i hope now you can enjoy Sam & Max Hit the Road with the mother 3 super mario 64 and runescape soundfonts ya ya ya