Use case diagrams typically represent the context of a system and system requirements.

1. Usually, you begin at a high level and specify the main use cases of the system.
2. Next, you determine the main system use cases at a more granular level. As an example, a "Conduct Business" use case can have another level of detail that includes use cases such as "Enter Customers" and "Enter Sales."
3. Once you have achieved the desired level of granularity, it is useful to have a convenient method of expanding or contracting the use cases to grasp the scope and relationships of the system's use case views.