Background Soundtrack issue

I would like to have a 35 second soundrtrack playing (looping) in the background of my site.

My problems are:
How do I get the soundtrack to loop continuously (stream or event)?

Why does the soundtrack play again (start) when an instance of it is already playing (creating 2 layers of sound)?

I am a beginner and I have 4 books that dont seem to give me the answer to my problem… :puzzle: