Karaoke help

[noidea]

I always record with audacity and never had a problem. Just put the instrumental on a playback on headphones and sing over it. If the backings overpower you that means you are singing either not loud enough or not powerful enough, you can change the volume of every track you record.
For the delay you can move your recording to a few milliseconds earlier or later, one of the cursors can do that.