Below are links to two helpful articles regarding the stimulus. This one is a calculator to determine how much you will get. You will need your most recently filed return (2018 or 2019) to determine the income: Stimulus Calculator
The second is a concise overview of the program. Note that the payment is an ADVANCE of a 2020 tax credit, so there will be a form to file next year to reconcile amounts already received if you did not get the full amount. Guidance is coming soon so stay tuned: American Rescue Plan