Easiest install is probably using ORAK's non-root version. Follow the instructions in his post [Only registered and activated users can see links. ]. No hex editing or root access required. Just copy the correct folders into either internal or external SD under Android/data/... Install the APK, reboot, and it should work.
I downloaded the external SD card version and installed the maps on the external SD card of the S5 at:
/storage/extSdCard/Android/data/com.garmin.android.apps.gmobilext/files/Garmin/Map/
Bookmarks