Educational Payroll Flow and Data

Data: people, names, salaries, salaries, tax tables, pension rates, health insurance, hours worked etc.
Flow: read hours worked this period, calculate salary, print payslip.

My suggestion is that if you don't know anything about the domain of the application, you better get some (really a lot) of input from key stakeholders before you start building things. You will save yourself a lot of wasted time if you plan before you try to build. If you're doing this as a job, get your specifications in writing, in detail, preferably signed in blood ;-)

Good advice, only usually nobody signs anything even in ink. :-)
--SA