hi ,
here requirements are give to the client .based on we write
the scenarios 
ex: login page 
scenarios on login page :
1.enter the url and click whether the page is open or not
2. the default focus cursor should be on user name
3. password should be encrypted format
4. password should not copied
5. input domain testing on user name and password
6. properties check on buttons 
7.functionality check of the buttons in login page 
8.authentication testing
9. check the session time out
10.check the cookies
like .....................