I heard there is an additional amount people with children are supposed to get per month, starting in July. How do I make sure I get this?

There is no longer advanced child tax credit. 

Q. Is it true that there is an additional amount people with children are supposed to get starting in July?

A. No. That's only  congressional proposal, at this point in time.  Even if passed, it's unlikely to have an advance monthly payment provision.

Reference: https://www.kiplinger.com/taxes/congress-negotiating-child-tax-credit