If you plead not guilty, the judge will preside over a trial to determine whether you are guilty or not guilty. The trial may be held that day, but in certain circumstances it may be rescheduled.
In a trial, the prosecutor first will call the state's witnesses (witnesses against you). They will answer the prosecutor's questions and present any other evidence they have. When the prosecutor is finished with each witness, you, or your attorney, will be permitted to ask them questions about their testimony.
When the prosecutor's case is complete, it will be your turn to call witnesses and present evidence on your behalf You may testify, although you are not required to do so. If you testify, the prosecutor can ask you questions (cross-examine you). After all witnesses and evidence have been presented, the judge will decide whether you are guilty or not guilty If you are found guilty, the judge will impose a sentence.