You got 3 versions of the same mapset for different purpose. The one you need are:
osm_routable_mapsource: To use the mapset in Mapsource
osm_routable_gmapsupp: To use as a precompiled mapset on your Garmin device (no Mapsource needed)

As you didn’t mention where you downloaded these files (there are many provider of Gamin-Maps based on OSM-Data) try to unzip osm_routable_gmapsupp. There should be a file gmapsup.img. Copy the file on the SD-Card of your Gamin-Device in the subfolder \garmin. Turn on you device and you should have your map.