How do you put music in the background of a song that your singing like they do on these karaoke songs?

Question

Example:If I was singing Amazing Grace and I wanted to put music in the background of that song while I sing. How would I do that? 

Answer 1

You start with a backing track FIRST - like a karaoke track - and you record yourself singing over it.  If you want something that caters to your own interpretation of a song, you need assistance from highly skilled people in music production - and more than likely, fine live musicians.  

Apologies for previous typos, now repaired.

Answer 2

You just need a midi file of the song you are looking for.

for example:-

amazing grace.midi

Answer 3

If this is how you worded a question meant to ascertain how music production works then you ain't gonna understand the answer. No one could dumb it down that much. No one.

Source(s): Musician that's released 3 studio albums I produced myself.