Audio while recording

I am new to this I have an audio track that plays ok, but if I wish to add a vocal to it , why when I record is there no sound from the audio need this to add vocals to ,
I have recorded once worked a treat , but now no sound, anyone help please

That’s what Preferences > Recording > [X] Overdubbing does. Make sure none of the other settings in that panel are checked.

Also, there is an overdubbing tutorial.

http://manual.audacityteam.org/man/tutorial_recording_multi_track_overdubs.html

Koz

Thanks worked. A treat I am learning , it’s a great program