So although I know I can pair my phone with the nav I wanted to copy my mp3 music to an SD card and I can’t get it to work, any help on what to do?
I'm way back here with a Nav V. For me to get MP3 music to it, I just plugged into into my computer's USB port, mounted the drive to my desktop and then dragged my MP3 files into the SD Music Folder.
IIRC, you have to format the SD when you insert it for the first time.

This creates the music folder on it.
I don't recall because MP3 playback on the NAV was so horrible, I switched to using my phone instead.