You are combining information from both return. Line 18 asks from amounts previously refunded.
Enter the overpayment from your original return. If your original return was changed by the IRS and the result was an additional overpayment of tax, also include that amount on line 18. Don’t include interest you received on any refund. Any additional refund you are entitled to on Form 1040-X will be sent separately from any refund you haven’t yet received from your original return.
See the instructions for Form 1040x for more information: https://www.irs.gov/instructions/i1040x
