Stereo to mono

I would like to modify a recording that I recorded on a “stereo” setting that only plays through one channel only (a talk recorded on a Zoom H4) and make it mono so it plays through both speakers. How do I do this?

Black Down Arrow on the left > Split Stereo Tracks.

Select and copy all the sound in the valuable track > paste it into the blank track.

Black Down Arrow on the left > Make Stereo Track.

Technically, that gives you a two-track mono performance which is what I think you really want.