Tutorial Set your own in game music.

[Fedelis]

If this is a repost then... oh well, tell me and I'll delete.

Basically if you want to get rid of the shitty in game music and use your own instead navigate to:
Gpotato->Flyff->Music

Now find the song you want to replace, we'll say we're replacing BgmBaGeneral. Copy the name of the file (BgmBaGeneral) and move it to a different folder for safe keeping.

Now find the song you want to replace it with and drag it into the music folder. Rename the song to BgmBaGeneral. Right click on the music file and select Properties. Check the "Read-Only" box and hit OK.

Your music should work in game instead of the default music now.