I'll have to check. I believe I did it via a Reddit post with the author posting about the app, and another guy did posted a file with the XML fixes to allow it to import. I bet I could just export from the app and you could use that, I am guessing that would be in violation of the WotC IP...
I've been using the 'Fifth Edition DM Tools' on Android. 5 bucks, and imported all the monsters. I bet it will be outdated now that the whole licence thing has come down. Going to see many prettier apps and preloaded with goodies now I am thinking. Anyway, no super intuitive, but really useful...