Get trouble with attr "document" of use case

I’ve read a doc say that"attribute called “document” of a use case has 2 ways to describe:use a paragraph(natural language like english) to desc or use an activity diagram". But in chapter “activity diagram” absolutely doesn’t say about that? What is my problem?
PS:somebody can help me to find any document about UML which is simple, short (because of my english skill:">). Thanhs a lot.

Hello Klein,

Thank you for your message. A use case is modeling a user’s goal. And the goal can be described textually with natural language. As use case is a user’s goal, different scenarios may happen when user trying to achieve the goal. Activity Diagram can used to model the overview for all execution paths of the use case. Normally you can create Activity Diagram as sub-diagram of an use case to elaborate the execution paths.

VP-UML (Professional Edition or above) support defining the details of use case with Flow-of-Events, and you can generate Activity Diagram of the use case based on the Flow-of-Events. Details about this features can be found at

Besides, we also provide online training course for learning UML. The online training course can simply viewed by browser. Details about our online training center can be found at

Feel free to contact me if you require any further information.

Best regards,
Rain Wong