The "Sounds" folder not exist after skin installation,
So I copy it from other skin and it works.
This is intentional. There is no sound theme included.
OK.
I think it will be nice if you can add an option for enable/disable sounds so the user will make the choice if he want that.
But as you wish, it's not something critical (As I said I already copied it from other skin)
Thanks on your great skin.
Kodi already includes a default theme called busting bubbles....