To use the three maps individually without the package, do as follows:

If you have a Nuvi series 2x5, 7x5, 465T, put one map, CNBR for example in /Garmin folder in internal memory renaming it as gmapprom.img and put the other two in /Garmin folder on SD card renaming them as gmapsupp.img (TRC for example) and gmapsup1.img (Autoguia for example);

If you have a Nuvi series 1xxx, 2xxx, 3xxx, 40, 50, put all of them in /Map folder in SD card or internal memory using any preferred names like CityNavigatorBR.img, TracksourceBR.img, AutoguiaBR.img