EDIT MUSIC IN AUDACITY
Not always easy to find good help on the net, but this particular video on music editing on ProShow Gold was quite good. It's easier to have patience with people who do things well.

Here is the user's guide to ProShow Gold.

                                                                             This was helpful for me to learn how to line up 2, or more, different tracks. Yay!!  The instruction for that starts at about the 4-minute mark.  Highlight the track. Click on the 2-sided arrow that points in opposite directions, and hover that arrow over the track. Then slide the track to the position that you want it. And that's it. Pretty simple once you know how.

Here is a short list of sites that list WWII songs.  Check them out.
https://archive.org/details/WWI1256I
https://archive.org/details/WWII_News_1940
http://www.loc.gov/rr/program/bib/WW2/WW2bib.html