Cubase AI 5 - Instrumental while singing

Hi everyone,
I have a friend that has bought a yamaha audiogram to start making covers for youtube. The question is, how can she put the instrumental/karaoke playing while she sings, but without recording the instrumental (just record the voice)?
After that she could join the vocals to the insturmental downloaded from the internet… So that the voice is timed with the music


She needs to import the instrumental to a Stereo track in Cubase and record her singing into a mono track. And she’ll need to sing using headphones so that the instrumental doesn’t get recorded through her microphone.

Aligning to a downloaded audio track after the fact is virtually impossible. At least if you want it to sound right.