How can I do away with my anger bitterness insecurities and how can I forgive myself and my past.

Anger is said to be a secondary emotion,  it is the halfway point, so we need to keep going pass it and further down into our emotions.   It often ends up to be hurt, disappointment due to some unmet need.  Often what gets in the way of focusing on emotions is that fight, flight or freeze programming.  The adrenaline and cortisol rush in saying attack or run.  It is not mindful it is more like a bad habit because it is a habit that we have gone to as a way to cope--maladaptively cope for many years--so it is just like it is second nature to us.  We think it is a way to protect ourselves--cope.  Yet, when we have calmed down and can think more straight then we often if capable of being honest with ourselves see our errors and have some regrets or justify our behavior by pointing at something external.  We point at something outside of ourselves to justify our actions.  He/she was late,  he/she talked rude to me,  he/she is calling me a liar or attacking my personhood in some way.    Instructions on how to manage anger:  first--one must pay attention by noticing themselves becoming disturbed.  Notice how you are experiencing your disturbance--once you notice that you are getting upset whether you notice your strong negative thoughts, strong feelings,  bodily sensations one or all that is when one must immediately start to practice diaphragmatic breathing.  There are a million youtube videos on how to do this.  Once you start breathing it is physiologically impossible for the heart rate to not slow and the negative harmful chemical--adrenaline to slow.  Now when you are breathing there is a count going on such as breathe in counting to two and breather out counting to four.  two in and four out so that means that two in will have to be big and deep because you are counting four out. this counting distracts you from your negative thoughts and makes you focus on your counting and breathing--so it like taking a time out--  pausing.    It is at this point you ask yourself are my old behaviors and thoughts effective------the honest answer is, no.  And you know it because for years they have not served you well.  You ask yourself,  what would be the effective way of dealing with this situation?  It might be say nothing.  It might be take a walk.  it might be to laugh at how silly this is. Or it might be to realize that it is not the "me show" meaning that what others do is about them not you--it has nothing to do with you, it is bout them and them only.   It is their behavior, their attitude, or emotional state not yours.    Now as far as the bitterness, there is also a process to go through there also--it is a self-inventory of resentments and to see how hanging on to these resentments is like drinking poison and hoping it will kill the person you are bitter at.   It is a fact-finding proposition of looking at how your bitterness only hurts you and no matter who has hurt you or wronged you they are not going to fix it for you so your left to take responsibility for that if you want more happiness.  If nothing changes nothing changes, right.