I just went through this exercise. You can import a GPX file. But in my case that wasn't satisfactory. You loose all your icons and colors. If thats not an issue for you its easy. I had to use homeport (Garmin) to export my points to a CSV. Also export a CSV file from the TZT3. Use these 2 files. Along with the attached Furuno format file to create a CSV file with the correct points, colors and symbols. I could get a lot more detailed and you might have a better way but thats how I did it.
