How do i properly add The $1200 stimulus but i did not receive the $600 stimulus

You just enter the 1200 you got in the first box and enter 0 in the second box.

When you go through the federal review tab it will ask how much you got if any.  Enter a 0 in the box if you didn't get one.  Or to enter your stimulus payment in TurboTax, type "stimulus" (without the quotes) in the Search box, then click the link that says "Jump to stimulus."

After you have entered your tax information and are ready for the Federal Review, it will be the first question.

If you are trying to trigger it, you can go to Other Situations, answer any questions and click Done. The next automatic selection is Federal Review and it will ask about payments received.

If you didn't get one or both of the Stimulus payments or qualify for more it will be the Recovery rebate credit on 1040 line 30.  It either adds to your refund or reduced a tax due.

If your 2020 income is too high you won't get prompted for the Stimulus section since you can't qualify for any more.  And you don't have to enter what you already got and don't have to pay it back.  1040 line 30 is only if you qualify for more not what you already got.