How to change the key of the BGM? (OWO!'')

Its probably something really simple but i dont know how to do it ><

I use Audacity for that

just import whatever off vocal you want to change the key of and higlight it and then go to the effects tab and choose change pitch, and choose how many semitones you want to raise or lower the bgm, I've seen most guys on Nico doing 3 semitones of raising pitch, hope this helps

Ohk~~ thankyou ><

Audacity isn't the best though. Sometimes it produces low-quality sounding off-vocals after pitching down. Adobe Audition is slightly better. Just for future reference. owo