Thanks! I didn't know that existed, and I learned a number of things while reading through it. It's pretty condensed/dense, but it covers all the features, it looks like. Not to be confused with a tutorial - which also might be helpful.
I took this opportunity to download the git repository, and try to resolve what the mysterious 'GEL' meant on the instrument panel. Turns out 'Ground Elevation', and 'DNL' means 'You need to download the ground elevation data, you idiot!' :)
And I found that the 'Documents' referred to for the KML file are internal to AvareX, so looking for it on my phone's documents are an exercise in futility. Read the manual, John!