How do I file taxes if my parents are not U.S. Citizens?

I am a U.S. Citizen, but my parents are not. I'm currently a student, but my parents support more than half of my financial needs. I have earned income before, so I do need to file my taxes; this is also my first time filing.

In Form 8615, I am asked to enter my parent's SSN, which they don't have. I am unable to continue without entering my parent's SSN. What should I do?

 

Any information is appreciated; thank you.