XDJ-RX3 No sound

I'm brand new to this. I set up my new XDJ-RX3 and connected it to speakers. I have inserted a USB thumb drive with MP3 music. My music populates on the touch-screen and I can load songs and play songs, but I can't get any volume through my speakers or headphones. I haven't downloaded and installed Recordbox or Serato. Should I still be able to get sound from my MP3s straight from a thumb drive? What am I doing wrong?