Strike to Defend Yourself! (If you must)
Whenever possible, the best option is to avoid physical escalation. Controling your temper, maintaining distance and the communication (verbal and non-verbal) are important areas to focus on in this regard.
However, it is good to have a basic understanding of how to defend one self if necessary.
In the video below I focus on striking.
These are not the only options. The right move will depend on you, your opponent and the situation.
I encourage you to research further, but if your focus is on self defense, then I advice you to look for simple and effective techniques, principles and strategies, and then train to execute them under pressure.