Basically you put the GPX, BMP and MP3 files into a folder. Bbest to use a series of different folders for different items and the POI Loader converts the files in the folder tree into a single POI GPI file on the GPS.
I have an issue, if I use POI uploader the file gets converted to .gpi, the issue is when i look a waypoint in the file i uploaded, it comes up; however, there isn't any "go" button displayed. I tried Base Camp and Road Trip to upload the file; however, they end up in my favorites folder, not way to search (there are over 2000 waypoints in the file). I have tried send in Base Camp and it put in a temp file with the name "temp.gpx" in the gpx folder, i renamed it "cccc d", still did work.
regmikewall, I have a similar problem on the 3790T where no GO button shows up on screen. It is only happening with some POIs and others are working fine. It seems consistent so it may be something in the POI itself