Resond to a summons

I live in New York state and I was given a summons naming me in a law suit. I teach classes for an Adult education art center and one of my students was burned in my class. I was given a summons which named the school, myself and the makers of the equipment. The summons said I had to respond within 20 days. The school said that they had insurance to handle it. My question is, should I also respond and how(there were no instructions or form on summons) or is the school resonsible for me since I am under there employ? If I have to respond do I need a lawyer to do so?