Read the instructions for the top part, for Simplified refundable child tax credit.

https://www.irs.gov/instructions/i1040s8

And read the part for "abode:"

This means your main home was in the 50 states or the District of Columbia for more than one-half of 2021. Your main home can be any location where you regularly live. Your main home may be your house, apartment, mobile home, shelter, temporary lodging, or other location and doesn’t need to be the same physical location throughout the tax year.

Try this Turbo Tax article:

https://turbotax.intuit.com/tax-tips/family/what-is-the-irs-form-8812/L1HbgYQqE

Try this article:

https://www.communitytax.com/tax-form/schedule-8812/

There are a lot of resources on the web, and those meant for the tax payer are often written differently than the IRS info.