where is music stored for car playing via usb

[callmeMark]

Hello all ,

Where is music stored which my car stereo plays via usb device ? 

I have lots of music on my device (s10 lite) and I wanted to know the location of the music files so I can add and remove music files 

[TRY2HELP]

open my file , then you see audio, that where your music is

[callmeMark]

its playing all music except the 30 songs what I have on my sd card

[callmeMark]

and thank you for your help