Here's a much quicker read than the linked tutorials.
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To create a soundtrack for your game, simply create one folder in your scenario's "Sounds" folder. Call it "Build".
In this "Build" folder you can stick as many mp3 files as you wish and call the file names whatever you want as well. The only thing you need to be aware of is that these mp3s MUST be 128kbps @ 44KHz.
Next, in your scenario's "Text" folder, create a blank text file and call it "Music.txt". In this file you simply list all those mp3 file names, together with the right file extension, each on their own line. The order you list them in is the order the files will be played in.
That's it, really.
(If you want specific music for specific eras, then those linked tutorials tell you how. Though personally I find it more hassle than it's worth and it's more enjoyable to just make one long soundtrack).
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If you want to create diplomacy music, that's easy too, though a little bit different.
Also in your scenario's "Sounds" folder, create a folder and call it "Diplomusic".
You then populate this Diplomusic folder with four tracks for each of the five culture groups - 20 mp3 files in total. There is one track for Peace and one track for War. There are also two periods, Early and Late.
So, for example, the North America culture group will have four diplomacy music files - containing whatever music you want - but the files MUST be named as follows:
DipNAEarlyPeace.mp3
DipNAEarlyWar.mp3
DipNALatePeace.mp3
DipNALateWar.mp3
Just do the same with all the other culture groups, bearing in mind the necessary 128 bit rate, and you've got the full deal.
(If you don't provide mp3s for any of these culture groups or periods the game will simply reference the vanilla music).
There it is.
