Download the latest version of this plugin and put it in:
sd:/atmosphere/contents/01006A800016E000/romfs/skyline/plugins
Create a folder called Randomizer in the following path:
sd:/atmosphere/contents/01006A800016E000/romfs/
Then replicate the ARC path for the file you want to randomize.
For Example:
Stream - sd:/atmosphere/contents/01006A800016E000/romfs/Randomizer/stream;/sound/bgm/bgm_crs2_02_senjyou.nus3audio/*.nus3audios
(Randomizes song anytime the song "Battlefield" is played)
Arc - sd:/atmosphere/contents/01006A800016E000/romfs/Randomizer/ui/message/msg_bgm.msbt/*.msbt
(Randomizes msbt file anytime msg_bgm.msbt is loaded)