Injured Spouse Form 8379 Child Tax Credits

I have earned 100% of our income this year. My husband is a stay at home dad and has outstanding student loans. As a result, all of our tax return was withheld, so I am filing an injured spouse form. I'm very confused on what to enter for lines 16 and 17. We have two children, both biologically mine.

For line 16, instructions state "Form 1040 or 1040-SR (after 2017): Because the personal exemption is not available for 2018-2025, enter -0-."

The instructions state to fill line 17 with what is reported on line 13a from the joint return. On our return, 13a states 0, but the Schedule 3 line 7 states 648. "Form 1040 or 1040-SR (2019): Include any tax credits (except the earned income credit) reported on Form 1040 or 1040-SR, line 13a, or Schedule 3 (Form1040 or 1040-SR). In columns (b) and (c), allocate any child tax credit, credit for other dependents, child and dependent care credit, and additional child tax credit to the spouse who would have claimed the qualifying child (or qualifying relative) as a dependent if separate returns had been filed." 

What exactly should I be entering for the number of exemptions for my children and where? Should I be entering the number of children that we have or the dollar amount under the "Additional child tax credit" on our joint return? I'm so confused and don't want to cause a further delay in processing this. We were not even aware of the garnishment prior to receiving the update on Saturday.