You were getting two different provisions of the new American Rescue plan law mixed up.
First, there is a $1400 per person stimulus payment, that includes dependents. The IRS has not announced how they will pay this yet.
Second, there is an expanded child tax credit. This takes effect July 1, and is to be paid directly to taxpayers monthly, or as often as the IRS can make practical, rather than having it included on any tax returns. The IRS has also not released any information about how they plan to make these payments.
