How does it the American Rescue Plan Act of 2021 $300 month child tax credit work?

I am told that the American Rescue Plan for 2021 is supposed give a child tax credit on my taxes and I would get a payment of $300 month.  But I would need to complete a form.  What form is that, and is it updated on the Turbotax software?  I am a bit confused on how this works, and what form I would need to complete on the software.