To export audio to a file, click the item you wish to export, then right-click Export Audio and Data
A box will appear asking you which folder you would like to export the item to. Most importantly, it asks you (in Options) what exactly you would like to export.
For audio-only, check the audio box, then pick from one of the options on the right-hand side.
When done, click the "Do Export" button.
The file will then be exported to your chosen destination.