How do I add an mp3 to my tank game?

I download music from incompetech, but I cannot figure out how to put the music in my game. the link:
the music is Nonstop by Kevin Macleod

You need to upload it to a mp3 hosting website such as dropbox or kiwi6.

Then copy the url/link

It should end with .mp3

Btw i think you have to refresh the page after writing down the address for it to work