Open your multitrack editing program. It should open to the multitrack view window.
Right-click on one of the tracks and select the "Add File" option. Depending on the program, this may be written one of three ways:
"Open Audio File"
"Import Audio File"
or
"Add File."
Select the karaoke music track that you wish to sing to. It will be added to one track in the program.
Plug a microphone into the microphone jack on your sound card. This jack is normally red.
Plug headphones into the audio output on your sound card. This will allow you to hear the music that you are singing to without receiving feedback through the microphone.
Arm the second track for recording by pressing "R" on the track label. Adobe Audition, Cool Edit, Acid Loops, Fruity Loops and Garage Band are just some of the programs that arm their tracks this way.
Press the "record" button to begin recording your vocals. Begin singing the song.
Press "Stop" when you are done singing the song.
Press "Play" to review what you have just recorded. You can right-click on the track you just recorded to adjust the volume or balance of the track.