Let's clear up the major question about this form right away: it is part of the child's tax return, not the parent's.
As a result, the only numbers we can carry automatically from elsewhere in this tax return are the child's numbers, not the parent's. You have to manually enter on this return any numbers from the parent's tax return that you need.
The goal of this form is to assure that some of the child's investment income gets taxed at the parent's top tax bracket, that is, that the child's investment income gets taxed as if it were earned by the parent. This form prevents the parent from using the child as a tax shelter.
This requirement applies to investment income, such as interest and dividends, but it does not apply to the child's wages and other earned income.
There is, if you qualify, another way to do what this form does, and that is to skip this form, but to attach Form 8814 to the parent's return.
Usually Form 8814 will result in a higher tax because fewer deductions are allowed, but to be sure you should compare the results of both methods.