When asked the question did i receive a 3rd stimulas i responded no that is incorrect and i need to correct that and enter an amount where do i do that?

That question is in Federal Review for the recovery rebate credit.   But if you already filed your tax return you cannot correct it.   The IRS will find the mistake and correct it for you.

i have not filed yet 

Then go back to Federal Review and change the way you answered the question about the EIP payment.