Usb stick not usable

[Chairon22]

Hi everybody, my Projekt is almost at the end... Standing right now before my hopeful last problem. I have running the latest buster with one line phoniebox. Everything perfekt even the rfid reader works. Great 👍

Now I would like to use the musik on my USB stick which is automatically mounted in media/pi/... Buster does that by itself.

How can I get phoniebox to read from there. I tried the instructions from miczflor, but I seams to not work.
I tried and read from other forum, but not really knowing what I'm doing this is also not my solution. I hope someone can help me?
In raspbian I feel like a 5 year old, sorry...