After approval of an I-130 the petition is forwarded to the Department of State, via the National Visa Center or "NVC". The NVC will handle the processing of the visa application, including the Affidavit of Support.
Once the petition is received the NVC will send you a notice containing the Fee Invoice and instructions for your case. You will first need to pay the fees and then you will be provided with cover sheets to file your I-864 and civil documents. You, your attorney, or your parents will need to complete the online visa application and file the documents/affidavit of support with the NVC. After reviewing your complete packet the application is forwarded to the consulate to schedule the interview and adjudicate the visa.
This answer should not prevent you from speaking to a lawyer and disclosing all facts about your case. Additionally, it should not prevent you from filing to see if you are eligible. Please seek an attorney for an initial consultation to review all the specific facts of your case.