The D.S. al coda concept is a good way to repeat a section without adding a zillion pages to a piece, and this song explains how it works. We've set the tune to an exciting four-on-the-floor techno house groove that should motivate young singers. Singing the concept will help them learn it well.
D.S. is shorthand for dal segno, which in Italian means "from the sign." In this case, the D.S. occurs at the end of measure 28, and the sign is at measure 5. It's only fitting that a song about the D.S. al Coda should contain one! (from Music K-8, Vol. 20, No. 1)