How to turn on the older Spi Digital Audio Player?

-_- ok so, i have looked over the internet dozens of times, and i cannot find an answer. I have an older version of the mp3, its more square, only plays music, thin little screen that scrolls the name/artist that you're listening to, and thats about it. it has a forward and back buttons, stop/play, volume, and a button that says "M"? i had lost it a long time ago and had tossed the manual, and just recently found it. I have added all of my music onto it, I just can't seem to get the thing turned on? do you just turn the thing to "on", or what? it shouldnt be this complicated o.o