This Library is deprecated. Please check here for the new library:

https://github.com/DFRobot/DFRobotDFPlayerMini

DFPlayer-Mini-mp3

Install instructions:

Download file
decompress
copy inside folder to your Arduino library folder
restart your Arduino IDE

Check the wiki for more information: http://www.dfrobot.com/wiki/index.php/DFPlayer_Mini_SKU:DFR0299