If you do not have an attorney, contact the U.S. Bankruptcy Court clerk's office in your district and they can give you the form you need to complete. It may also be available online through the clerk's office as a PDF fillable document. Once you prepare it, you need to properly serve it.
It's very difficuly to get student loans discharged in bankruptcy, so you're best off with a lawyer. Also, please see the guide linked below, or one like it, written for non-lawyers.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.
Discharging student loans in bankruptcy is almost impossible. In order to meet the "undue hardship" requirement, you have to show that, due to your specific circumstances, you will never be able to pay the loan off. Courts have allowed discharge of student loans in only extreme circumstances. If you still think your situation warrants this, you should speak with an attorney. An adversary proceeding should not be handled alone, as it's very easy to make a mistake or overlook a rule.