dfr02999 DFRobotDFPlayerMini mp3 totally random problems

HI

I am trying to use the dfr02999 DFRobotDFPlayerMini mp3 board with arduino ( the final project will use arduino RP2040 connect)

for some reason I dont understand I am getting totally chaotic results.

I can get some file to play on arduino Uno but it is not the file I choose, often it just starts playing some random file and repeats it a few times.(e.g I play 4 files and the randomly play 3x)

I suppose file 1 = 0001.mp3 ? 

on my setup 1= 0004.mp3… 

so what I want to do is play a few different short files one after the other without delay and then stop.

first get it to work on UNO and then port to RP2040( different serial problems)

any help please?