Payroll Setup(Admin-->Payroll Setup) is the area you manage mainly what your payroll weekend date is as well as any weekly/daily hours rules. You can also manage which types of timesheets users will have the ability to enter:

The Hours per Day Rule and Hours per Week Rule only apply if Time In & Time Out is selected. The reason being is that overtime is automatically calculated on Time In/Out timesheets instead of manually entering OT when creating a normal timesheet(non-Time In/Out).