WAYS TO INSTALL:

1. data.win

- You copy the provided data.win file and replace the original one (backupping it, of course)
TIP: If there are no files named "data.win", opening the game would result in choosing the appropriate data.win file,
so I personally just rename the original data.win to "data_orig.win" and the mod one to "data_mod.win" for example,
and then choose what I want to play.

2. .xdelta

- You use either FB3 Manager or Delta Patcher to patch a VANILLA data.win, no others would work! (Atleast from what I've heard)

CUSTOM MUSIC:

You replace the audiogroup1.dat file in the folder of the game with the modified one. That's it. I have no clue how the FB3 Manager does it though.