You probably can get the forms for the petition for dissolution at the courthouse or online. They may also have a facilitator there at the courthouse to assist people in filling them out. The agreement the lawyer drew up will need to be signed and witnessed/notarized and made a part of the petition. Usually, both sides have to fill out certain forms. Go on your court's website to see if they have forms and instructions you can use. You may also be able to file for a fee waiver for the filing fee.
Disclaimer: It is impossible to evaluate a legal problem without a comprehensive legal consultation and review of all the facts and documents at issue. Consequently, this response does not constitute or establish an attorney-client relationship but is offered for general informational purposes only. Laws differ from state to state and each case turns on facts specific to the case and parties thereto, thus this answer does not constitute legal advice, and should not be relied upon as anything more than a starting point or suggestion that the questioner seek professional assistance from a practitioner in your state or county/parish, practicing in your area of law.
"Assuming" the documents your former attorney prepared are complete and accurate, you can file the Joint Complaint for Divorce which must contain the Settlement Agreement. You will need two other documents when you file. One is the Civil Case cover sheet, which the Clerk will give you to fill out at the time you file the Complaint. Second is a Rule 8.05 Financial Statement, which will need to be prepared and signed separately by you and your spouse. A pdf of that document can be downloaded at http://www.chancery10.com/formopen.php?id=13.
It also appears from the above answer that California courts are more helpful than Mississippi courts. There are no divorce forms online at a Chancery Court web site. Typically, no one at the courthouse will help you with any assistance, for fear of giving you legal advice.
In addition to the other advice given here, you must file the joint complaint, property settlement agreement and 8.05 financial statement with the Chancery Clerk in your home county. After it has been on file for 60 days, you must appear before the chancery judge with a Final Decree of Divorce to review.
You should ask the Chancery Clerk when the Judge will be available to sign no-fault divorce and contact his court administrator to get on his docket. When the Judge calls your name, you should take the court file and your Final Decree of Divorce to the bench. The Judge will review the documents and sign your Final Decree of Divorce if everything is in order. Remember that your divorce will not be final until the judge signs the divorce.
You can purchase some of the no-fault divorce forms online. However, I would strongly suggest that you pay a lawyer for an office visit and bring the documents that you already have prepared. Have the lawyer review the documents and pay him to give you a Final Decree of Divorce form that you can take to court.
Sign up to receive a 10-part series of useful information and legal advice about the divorce process.