I already filed and paid the taxes for this year but wish to amend this years return. Where do I put the money that I aready paid for this years return?

I filed my return early believing that turbo tax provided the best option.  However, I found out that if I don't take the standard deduction ( which Turbo Tax suggested) I will receive a refund instead of pay extra to the State of Maryland.  I wish to file an amended return but do not know how to include the money which I have already paid with my original return.  Where can I put the money that I have already paid for this year when I filed?