I can not repay the homebuyer credit. The last page related to the payment under this Task has only continue button that without any payment entry. How do I pay?

The amount of the payment is calculated based on your entries and automatically added to your 2018 tax bill. 

• In the interview for the credit, it appears on the screen, Your Homebuyer Credit Repayment Summary. 
  
• If you want to pay more than the minimum, check the box next to  I'd like to repay more than the minimum amount due and enter the amount you'd like to pay.
  

It will appear on line 60b of Schedule 4 of the 1040.