Your first pay run on Moonworkers will start as soon as you have one employee on the payroll for the current payroll.
You don't have any employees registered in the system
Add an employee from the my employee list page.
You have one employee registered
It is very likely that their starting date is in the future. Check their starting date.
Go to My Employees > employees list
Select your employee from the list by clicking on view
Go to Employment details
Check their start date
You have several employees
Restart your payroll cycle.