You should make sure that the player you are using does support mp3. If everything pans out an the player you are using does support mp3 files then the probable causes are either the extension is wrong and its not an mp3 file or the file is corrupted. I recommend that you use a reputable download site, peer to peer systems have been known to have corrupted files and deliberate problems inserted by others.
Another options to download another player and see if it plays the file as an mp3(if your phone will support this) if it does then you may have a problem with the player you are using. Since you are using a phone for this I would suggest trying the file on a computer and see if it works there. Also if other mp3 files play fine you should not need an add on.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.