When you select the worksheet, you are required to select from the front entry screen the year on which the What-if estimate is to be based. Refer to PAYG (GDP-Adjusted Instalment Estimate) Worksheet 2024
Year: Enter Yes at the required Year field to open the worksheet where you will see that the known amounts required for the calculation have been pre-filled. Alternatively you may click in the field and press [Enter] open the worksheet.