Becouse you have kitkat 4.4.2 you must first create this folder on SD: Android/data/com.garmin.android.apps.gmobilext/files/
Now i see you already copy folder Garmin on SD, so you must now move your Garmin folder inside files folder so then when you will open your Garmin folder, your path must look like this: Android/data/com.garmin.android.apps.gmobilext/files/Garmin/
Now from first post download apk that have in name this: storage/sdcard1/Android/data/com.garmin.android.apps.gmobilext/files/Garmin