So, if you wanna know how to transfer sound files to Bluestack SN folder:
1) Import the sound from Windows to Bluestack first.
2) Go to Android Settings, you’ll find em inside the “More Apps” tab.
3) Press “Storage” settings and press “Explore”.
4) Make a new window.
5) Go to the audio folders and copy/paste them to StickNodes\sounds folder.

Yeah, that’s all.
It’s hard tho. I’ve dicsovered them myself cus there’s no help from Bluestacks.