Along with the petition (or shortly thereafter), you would need to file "schedules" with set forth all of your assets, debts, income and expenses. As much of that information that you can gather beforehand (e.g., addresses of creditors, amounts owed, monthly payments, etc.) will help in expediting the process. Your attorney will need other information from you but the schedules are usually the most time consuming to put together.
You may want to get and read a book like the one linked below, 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.
Truly no 2 cases are alike so it is hard to give one-size-fits all advice. If you really and truly have no assets, then it should not be overly challenging. However, I would not come to the conclusion that there are no assets at risk in your case until I knew all of the facts.
The exact procedures, steps and protocols are spelled out in the Nolo book reccomended by attorney Koslyn. I highly reccomend that you get it and read it before considering putting ink to paper. The book goes through all the forms and procedures, telling you what you need to know at every step.
The other option would be to see a legal aid attorney or to call your state or county bar association for a referral to a pro bono attorney.
This answer is provided for informational purposes only. Actual legal advice can only be provided in an office consultation by an attorney licensed in your jurisdiction, with experience in the area of law in which your concern lies.