Save/load sound settings

I’m trying to create a save feature for sound settings. The settings use a slider and global variable to change the music based off of the value of the slider. I’ve tried to follow the official save tutorials on the GDevelop YouTube channel but I can’t get it to work and I have no idea what to do.

Here is the code


(The keys are temporary for now so I can just easily get it to work and later change the keys to be better)

And here is the global variable that I’m trying to save and load

Here is the in game settings screen