I need help resetting my new MacBook Pro

If this is an M1 (Apple Silicon) MacBook Pro, then you press and HOLD the power button till you see the macOS recovery show. You'll see the Apple logo and a message telling you to continue holding the button. You can release the button when you get into the Apple Recovery screen and then from there click Options > Continue. You'll get options in there to recover the computer and be able to reset it to factory defaults.

If it's an Intel Mac, then you press and hold Command + R on the keyboard while the computer is booting and you'll get into the recovery environment. There you can also go through the process needed to restart the computer and installing macOS back in factory condition.

Keep in mind that in this situation, you are going to need to know the password to your Apple ID. If you don't remember that, you're going to want to go through the process to get it to reset. This is so that if someone who shouldn't have access to your computer tries to restart it so they can gain access, they will not be able to. If you know the password to the Apple ID, you can enter that in the process when you are installing macOS again and you'll be able to get access back to the computer.