How would I add my recordings into an instrumental song?

Question

Just wondering.

Answer 1

change the recording into a wav

Answer 2

1) Buy music editing software such as cakewalk or protools (it MAY be possible to do it with windows movie maker, but I doubt it)
2) Play along to the track so it's the right speed, and record it
3) Paste in the original track and your new recording onto two seperate tracks
4) Mix it down into a single wav or mp3 file