Can I amend child tax credit using TurboTax? If so, how?

I need a step by step instructions on how to amend child tax credit using TurboTax. If I can. I’ve gone through it a million times and I don’t get anywhere. I click on child tax credit section and it only asks one question and pushes me through saying everything is correct. It’s not. If I have to file by paper, can someone tell me if I should check the box for child tax credit for ALL my kids or should I only check off the box for the two kids who didn’t get the credit? I don’t want to mess up and delay my amended return. I need this to get processed so I can do my 2020 return on time.