How to fill the 2020 amended return

I have filed my 2020 returns through mail. I made a mistake and it needs to be corrected. I want to know which website I can use to get help with the numbers I need to fill in the 1040x form. I can key in the entries from the 2020 return but I want the details to be translated back and should be populated in the 1040x form so that I can go ahead and paper file. If it was 2019 or previous it was relatively easy but because of the Recovery rebate credit and the child tax credit its little tricky. I am not sure in which section/point I need to add these details.

 

My issue was I missed to add my child as Dependent while applying for ITIN for her. The return got processed without the other dependent credit. I corrected the ITIN problem and the number got assigned. This is the only thing but I need to add in all the other numbers to get the numbers match. Please help.

 

Thanks so much.

 

Thanks.