4. Be sure to rename saved voice files to exactly the same name as the CSV/GPX file for which the alert is intended, but retaining the .WAV extension.
5. Place all files into one directory and use POI Loader to create POI.GPX on the GPS device (POI Loader converts all files and merges them into one)
6. I have not been able to discover or see any differences between CSV or GPX files, but it seems it is a matter of personal preference which one is used. CSV files do however allow for editing via a spreadsheet program.
7. I have still to work out if all files are needed or only "CUSTOMER" files. At present I have used all files, but I am getting multiple warnings for some POIs.
This was helpful, I'm new to all this & it has helped clarify a few things. I thought it was odd there was no one FAQ place that explained what files are necessary for which model and then what to do with them.