How do people move on from anger?

My goal is to be happy. To move on from anger and find peace and joy within myself, celebrate who i am, and focus on trying to achieve some of the goals that i set up. I have new drive. I've been angry for so long. My friend instigated a fight between me and her, in the street. She beat me up so badly, my family and i threatened to call the police. She called me on the day ten times, at least, begging for us to just talk. Two days later again she was on the phone to my brother for almost fourty five minutes, trying to get him to put me on the phone. I swore at her and called her every name under the sun. I told her to never, ever call my house again. I was livid. We were friends for 3 years, she was plagued by mental illness and was always hiding her insecurities behind me. We spoke to each other almost every day, we were i thought best friends. We could tell each other everything and anything. I'm trying to get past the anger now, i don't need to be angry anymore she's finally out of my life. The other girls who sometimes i kinda got along with, kinda didn't have blaitantly taken sides. One of them for definite who i never really liked anyway is on her side, and the other one who i was really nice to, invited her to my home, hasn't gotten back to me since i called her around the time. I did so much for my best friend, too much, i was an incredible friend. How do i move on from anger? Is it a process that i just roll with and it will be gone when it just goes, or is it something that i can speed up. I'm angry that people will never know the truth about what she was like, she had mental health problems which she'll never admit to.But she was attractive, and feisty, and that's all people saw and that's all they wanted to see. She's a threat. She's a control freak and very manipulative. You start to alienate people and cut them out of your life without knowing why. How do i move on from anger i did a lot for a supposed friend and had it thrown back in my face.Will the truth ever come out about who she is?