There was a section where I was asked questions about my letter 6419. I put in the wrong number for Box 2. Does anyone know how to get back to this and change it?

Here is a help article with instructions to get back to the place to edit your amount for Letter 6419.

That did not answer the question for box 2

To change the number for the advance Child Tax Credit payments reported on IRS Letter 6419:

• Type "child tax credit" in Search in the upper right
• Select "Jump to child tax credit"
• You will see Let's check for child and other dependent credits. Continue.
• Answer YES/NO to Let's start with where you spent the most time in 2021
• Say YES to Tell us about any advance Child Tax Credit payments
• Enter the amount of advance Child Tax credit you received.