How can character traits be defined using Aristotle's Golden Mean?

According to the Golden Mean principle, all character traits have two extremes—excess and deficiency. Aristotle further states that character traits cannot be distinguished from technical knowledge, in the sense that every professional engaged in an activity knows how to avoid excess and deficiency. It is this ability to balance between the two aspects that defines moral behavior and a person's character traits. For example, a courageous person will face some challenges head-on because they are not too extreme and avoid others because they are too dangerous. This person neither has too little nor too much courage, since he or she judges a situation before acting. On the other hand, a coward will flee without analyzing the dangers worth facing and those not worth it. He or she looks at the extremes only.
https://plato.stanford.edu/entries/aristotle-ethics/