How do you forgive?

Hello. My narcissistic mother died recently, and she went through with the ultimate rejection: she excluded my sibling and me from her will. My sibling was the golden child and had gone no contact with my parents, so as usual, l got punished, too, even if l did nothing wrong. l wrote about this last year in February and received much support and advice from Redditors.

I feel that in order for me to heal and move on, l have to forgive my mother. I’m struggling with finding forgiveness within me. So here l am again seeking advice. How do you forgive your narcissistic mother for all the pain she put you through?