After you have plotted the ride, you can then export a gpx file. If your garmin is plugged in, put the file in the newfiles folder either on your garmin internal memory or the micro sd card.
If you're using a an Edge Touring with RWGPS then I'd suggest you use a .tcx file and turn off the turn-by-turn navigation (that's what I do anyway). The Edge Touring is lacking the horsepower to do TBT convincingly, but does brilliantly with a .tcx file.
After you have plotted the ride, you can then export a gpx file. If your garmin is plugged in, put the file in the newfiles folder either on your garmin internal memory or the micro sd card.