I have one stereo track and one mono track. I want to make a mono track out of this. How?
Make sure you have safety copies of all your work (if your computer caught fire right now).
Select the stereo track with the button on the left.
Tracks > Mix > Mix Stereo down to Mono. That should give you two mono tracks.
Audacity will mix everything to one track when you Export.
Yes I see. Thanks Koz