After you file


@Lackers12 wrote:

I didnt get my first stimulus ck or the second one so I have to fill 1040x


Assuming that you are not a dependent and are Not eligible to be claimed as a dependent plus your 2020 Adjusted Gross income is within the range to be eligible for the stimulus payments - 

Did you already file a 2020 tax return for the Recovery Rebate Credit for the payments you did NOT receive?