Can I submit an application if the criminal proceedings are still ongoing or still have to start?

Yes, you can already submit an application if the criminal proceedings are still ongoing or still have to start. The perpetrator does not need to have been sentenced by the court, and if the perpetrator is acquitted you can also submit an application. Also if there are no criminal proceedings (for instance, if the perpetrator is not known or if you did not report the crime), you can submit an application.