Jingle Bells make a Joyful Noise!!!

In the middle of December a dear family friend (hi Mary Jo!!) sent the girls some jingle bells to play with.  Both girls love anything to do with music, especially Emma.  When any music comes on she will bebop back and forth, and they both love to bang toys together to hear the noise.  As soon as I opened the package, I placed the jingle bells on the floor for the girls to explore.  They immediately were interested with the shiny bells and each grabbed one.  Once they figured out that the bells made a sound they became intent on making them ring.  Such fun was had by all!

What is this thing?  Why does it have holes on the side?

Emma making a joyful noise, while Charlotte studies the string.

How do I make this work?