The RX and TX from the Arduino Uno or Nano will be 5V and will damage the MP3 player which requires 3.3V on these pins. Connect a 1K and 2K resistor like this (see the 20160612_200645.jpg file in this ...

16x4 LCD screen connected via an I2C adaptor; 8.3 filename restriction (although larger filenames can be played, with varying results) And more; For this project you will need. Arduino Uno or similar; ...