Cannot access Override Fields in Advice Register and Export

Trying to access fields in the Override Fields tab in the Advice Register and Export and they are all grayed out

• Munis
• Payroll Processing 
• Advice Register and Export

Clicking define before clicking on the Override Fields tab

1. Payroll > Payroll Processing > Payroll Start and Status
2. Click Advice Register and Export
3. Click the Override Fields tab
4. Click Define