I have an ongoing one against a former psychiatrist and am preparing one against a former therapist.

Depends on where you live. Some states (I'm assuming you're in the US) you just submit the complaint and a few months later they let you know what they decided. Others might have hearings or allow you to be more part of the process (so you'll get to see your therapist's response etc.). The licensing board should be on the state government website and include a description of the procedures.

Good luck.