Answer 1

Using js:
var music = new Audio() ;
music.src = "mlink.typeoffile" ;
music.play();
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new Audio() is setting the type of the variable!
.src is setting the link of the audio!
.play() is a function to play the audio!

Answer 2

To add background music, you have to learn JavaScript

Answer 3

You can not add background music using CSS.
You need to use JavaScript to add music.

There is a audio class in JavaScript which takes care of music in your website.

For example :
var background_music = new Audio();
background_music.src = " musiclink.mp3";
background_music.play();

Answer 4

pause() is the function which you use to stop the play.

There is another property called currentTime which is used to get or set the current time of song while it's playing.

Answer 5

Javascript:
new Audio ("yoursong.mp3").play ()