stm32f4-discovery-Audio_playback

Good evening,
I have a university project in which I use a stm32f4, I tested the program "Demo Example Wavplayer with USB Host" and it works
well but with only one sequence named audio.wav! I willing to test this example with several sequences! My goal is to read the sequence
following result has supported user button ..
Can you help me to find the right solution?