Struggling to vocode two audios

[frozen monolith]

I have looked up multiple tutorials, and none of them have helped me with my problem. I have two audio files that I'm trying to vocode. I realize that the stereo tracks cannot be split, so I stopped trying to do that. When I select either of the audio tracks (or both of them) and try to vocode them, I can only hear the original track with some white noise. Can anyone help me with this?

[rocky tundra]

You can split stereo tracks to mono using the track's drop-down menu: https://manual.audacityteam.org/man/audio_track_dropdown_menu.html

[frozen monolith]

Do both audios need to be split in order to vocode them?