class file

hi;

i am doing final year project to my university. but i have to submit interim report. so please help me.

actually i am doing "Human resource information system"

· Managing of employee details, Leave details/ Employee dismissals/Resignation/ Employee training/ Employee loans/ Maintenance of salary details/ Salary deductions/ Overtime calculation/ Monthly salary process. this is main objects. my problem is how i write use case diagram and class diagram and also sequence diagram. visual studio 2010 c# is fully object oriented language actually how i write class files and inheritance and so on....please help me and give some brief description to develop my project.

thanks