What is breaking a large topic into smaller pieces to better understand the subject

Classification

Explanation: this is breaking down broad subjects into more manageable parts. You can make things to be in smaller and more specific points or parts for better understanding. A text can be broken down into topics, then subtopics and even smaller topics created from the subtopic for better understanding.

bevy means a large group or thing of a certain kind.

showing or suffering from nervousness, fear, or a lack of confidence