You can start on your own. Write about your early childhood traumas. What are the things that hurt you? What things happened with no adult around to give you safety and comfort? Today, your writing and speaking can re-experience this event with a new more holistic experience.
And as I forgive my father for his loss of control and family, for the divorce, and for not taking care of himself long enough to see me and my kids. Today, I forgive him, but I am also learning to forgive myself for the failure of my marriage.