[pkscout]

Thanks for the link. I'd already given it a look but didn't find it too enlightening. It doesn't explain what to click and why. Nor does it explain (or provide a link to explain) simple things, e.g. does Digital = Pulseaudio/bluetooth? If not then how do you add a profile for pulseaudio/bluetooth? And what's a profile anyway?

I suspect there are many people who've installed the add-on and given up because the documentation is written for those who don't need it. Perhaps a YouTube video walk-through with a basic how and why might help the dimmer bulbs like me to get over the line.

Digital is just a name for the profile. It means nothing. You could rename the profile "Funny Clown" if you wanted to.  That is explained in the docs right in section 3.1.

By default two of the ten available profiles are enabled and named Digital (profile 1) and Analog (profile 2). From the settings (see below for details on the settings) you can rename the profiles and configure the other settings.

Section 3.2 tells you exactly what to do:

Audio Profiles saves the options from a handful of areas within the Kodi settings. Those are:

• System/Audio
  
• System/Display (always saved, only changed on profile change if enabled in settings)
  
• Player/Videos (always saved, only changed on profile change if enabled in settings)
  
• Kodi system volume (always saved, only changed on profile change if enabled in settings)
  

Once you have configured those areas they way you want, go to the Audio Profiles addon and run it. A dialog box will pop up asking you to select a profile in which to save the settings. 

To paraphrase, you set your audio settings however you want them in the Kodi system settings, then you run the addon to save those settings.  Want another profile? Change the Kodi settings, run the addon again, and assign that new set of settings to a profile.