I was trying to find information on how to assign a custom sound to my text notification.
I saw several posts regarding custom notifications for text messages, other than the ones Verizon gives you. This worked for me on a Commando 4G LTE.
I plugged into my computer with the USB cable.
I put the files I wanted to use in the Notifications folder on the internal storage.
These were all .WAV files, so I don't know if other types will work.
Voila, when I went to assign sounds, the files were there.