Basically, if you are the victim of the theft, the prosecutor will reach out to you and interview you and should keep you apprised of the significant events in the case.
If you are the defendant in the case, then your first step should be to secure yourself a criminal defense attorney to help you with your case.
Every criminal defendant has basically two very broad choices -- to either plead guilty or to fight the case all the way to trial. Pleading guilty can frequently be a to avoid jail.
On a first theft offense it's sometimes even possible to avoid having to carry a conviction on your record, though a deal like may have to be negotiated for you.
Before you choose trial, you would need to know your maximum possible risks and the strength and weaknesses of the case against you. So either way, a lawyer is an important part of the equation.
He can get to confer with the prosecutor and see police reports and discovery and share all that with you so that you can make an informed decision about how to proceed. He can also protect your rights.
For more specific information, you would have to share more information with me. How much are you alleged to have stolen? To your knowledge, who witnessed the incident? Did you sign a confession with the police?