The Payment frequency (Weekly, Fortnightly, Four-Weekly and Monthly) can be set up under the Pay Details tab in the Company screen. Other, less commonly used frequencies are also available under the Other tick box (Two Monthly, Quarterly, Four-Monthly Six-Monthly an Annually)
The day that an employee is paid (Monday, Tuesday... Sunday) can also be set up here. For Monthly employees, you can specify whether you want them paid on the first day or the last day of the month.
For Employees who are paid Fortnightly, Four-Weekly or Monthly, the payment week can be specified. For example, for fortnightly employees, you may wish to pay them every second Thursday, starting from the second Thursday in the year.
Finally, the default payment method can be selected here (Cash, Cheque or Credit Transfer). You are free to change this in the Employee screen for individual employees, but when you set up a new employee, their default payment method will be whatever you specify here.