It provides the following information. A brief description of Use Cases, Actors and how they are used in the development process. A section on the Use Case methodology used along with a description of the terms used. A detailed description of the Use Case Reports generated during the Use Case analysis of the proposed system. A brief description of how to validate these Use Cases.
Actors are basically users of the system.
They are actually user types or categories. Use Cases are what happens when actors interact with the system. An actor uses the system to achieve a desired goal. The collection of Use Cases should define all system behavior relevant to the actors to assure them that their goals will be carried out properly. Any system behavior that is irrelevant to the actors should not be included in the use cases.