You have to file a petition for divorce with the clerk at your local court. This can be done via a divorce attorney or just gets it done by a Pro Se, less the advantage of an attorney. Your spouse will be given a time-frame to give answers to the petition immediately your divorce petition is filed.
The court clerk will stamp the filed petition and assign a case number to it. The court will then schedule a date for mediation or hearing for temporary court orders once a case number has been assigned, and your spouse gives their response.