Step 1:
Download the music pack
Step 2a:
Go to C:\Program Files\LucasArts\Star Wars Empire At War Forces of Corruption\Mods\(Mod Name)\Data\Audio\Music
Step 2b:
Steam users go to----> C:\Program Files (x86)\Steam\steamapps\common\Star Wars Empire at War\corruption\Mods\(Mod Name)Data\Audio\Music
Step 3:
Copy and paste the Mp3 file's to the Music folder shown from Step 2
Step 4a:
Use an XML editor (for example I used Notepad) and open C:\Program Files\LucasArts\Star Wars Empire at War Forces of Corruption\Mods\(Mod Name)\Data\XML\MUSICEVENTS
Step 4b:
Steam users go here---> C:\Program Files (x86)\Steam\steamapps\common\Star Wars Empire at War\corruption\Mods\(Mod Name)\Data\XML\MUSICEVENTS
[After opening the XML file mentioned from Step 4, you should see something like this]
<MusicEvent Name="Main_Menu_Music_Event">
<Files>Menu.MP3</Files>
<Volume_Percent>80</Volume_Percent>
<Fade_In_Seconds>0.0</Fade_In_Seconds>
<Fade_Out_Previous_Seconds>2.0</Fade_Out_Previous_Seconds>
<Loop>Yes</Loop>
</MusicEvent>
Step 5:
Menu.mp3 <-- This is the menu music. Take the mp3 track you want as your menu music and rename that to Menu.mp3 and that will now become your menu song (Not all mods have the same naming scheme!) ---You could also edit Menu.MP3 to be the name of your song you want to play. Just copy and pase its name.It would look like this--- Badass_Score.MP3
Step 6:
Launch and enjoy!