The radio provides a passive soundtrack for you during your time in Sundry's Forest. A different song plays every hour and can (along with the position of the sun in the sky) help you identify what time it is.
The radio can be turned on or off by touching one of your VR controllers against the toggle switch at the top of the radio.
All of the music that plays during the game is either public domain or licensed via Creative Commons and sourced from the fantastic Musopen, which is a not-for-profit dedicated to providing high-quality recordings, sheet music, and textbook related to the study of music. A list of the songs that play and their respective licenses will follow shortly.