If you do not have any other form of status, allowing you to stay, you will likely receive a Notice to Appear. You will appear before an Immigration Judge for removal proceedings to tell the judge that you want to adjust your status as a defense from removal at this hearing. The judge will set a deadline within which you have to submit your documents along with a date for your merits hearing. At this hearing, you will present your case to the judge, the one you submitted to USCIS for your I-485, but you can also bring any additional evidence that you think will help your case be stronger. Also, you can bring witnesses to testify. After you present all evidence has, the judge will make the decision and may decide to approve your application. If the judge approves it, you will finally get a green card.
No matter what option you end up thinking is the best one for you, we highly recommend you get an experienced immigration attorney who will help build your case and advise you on what steps you should take, having in mind the specifics of your immigration situation. An experienced immigration attorney will best assess where the application failed and what it would take to succeed in moving forward.