How to get Form 8862 to populate correctly. i am entitled to CTC for my niece.

You can fill out Form 8862 in the Advance payments, Child and Other Dependent Tax Credits section, if you were notified that you needed to include one in your return.

1. In TurboTax Online, sign in and open your return.
2. Click on Federal in the right menu bar
3. Click on Deductions and Credits on the top
4. Scroll down to You and Your Family and click on Show More
5. For the Advance payments, Child and Other Dependent Tax Credits section click on Start or Revisit.
6. Continue in this section and you will be asked Lets check for  uncommon situations Check the box that says,  The IRS notified me that I need Form 8862 to claim Child and Other Dependent Tax Credits.

TurboTax will walk you through from there.