The rules for criminal law in Spain are completely different from those in the UK. The system in Spain allows anyone to make a criminal claim against another person without any Police investigation. The process is called a “Denoncia” and is made without an appointment at the Guardia Civil Police station.
In some cases, the judge will open an investigation and you will be requested to attend an interview at the court. The judge will decide to proceed or not and you would be advised if any court date is set, the interview will be carried out with lawyers present and a court-appointed translator.