IRS Question advance payment $3,600

In 2021 will the IRS contact parents, legal guardian to find out if next year 2022 they will declare dependents on there taxes?

I've heard about a 2021 Child tax credit advance payment. They say it is based on 2020 taxes.

I am confused because I'm working in 2021 will declare dependent and file taxes.

2020 I was not working, I lived with my parents they declared my dependent because I was living with them. I didn't file 2020 taxes no income. I wasn't listed as a dependent.

Now how can I contact the IRS to let them know that for 2021 I am working will file 2021 taxes and have a dependent.

Will they just send $300 checks to my parents even though we don't live there because of the 2020 taxes.(Now if I file my taxes in 2022 for 2021 taxes. I am entitled to the $3,600. My Parents will the IRS request the $300 advance payments $3,600 to be paid back to the government)