I need to find out how to send back my faulty phone and get it replaced!

If it's within 14 days of purchase, simply return it. If you're within 1 year of purchase, contact Apple Support or make an appointment at an Apple Store.

You can go to a nearby Apple store in your community, to make sure you get a spot, make an appointment with Genius Bar. During Omicron, I'm not sure how many stores are currently open. But make a Genius Bar appointment for the date that is soon. If it's under warranty, you can get a phone to replace it. Good luck.