Is a "Total Overpayment" amount greater than "0" for "2018 State Tax Refund Information" something I should enter in the "Total withheld/pmts" textbox for 2019?

for state tax refund info  you enter the refund that you got from your state last year.

But if you did not itemize, there will be no effect and you can enter zero.

This is not 

 something you should enter in the "Total withheld/pmts" textbox