Once you know which county court, you need the courthouse's address to put on the forms you file to start your case. You can find courthouse addresses and contact information on Find My Court.
Sometimes larger counties have multiple courthouses where you can file a small claims case. If there are multiple courthouses where you live, you may need to ask a clerk or check the court's website to make sure you're filing in the right one.
Once you know where you can file, start filling out your court form that starts your case.