How to export selected audio
You can export any or all of your audio in to a separate single audio file.
You can choose whether to export with changes to your playback settings (enabled by default); Noise Cancellation, Speed, Volume etc.
Highlight the audio you want to extract.
Click on the export button (or right click) and chose 'Selected Audio' from the drop down list.

You will then be able to choose a filename and format for the exported file.
A single audio file will be created containing all the highlighted audio.