@CJJONES62
You need either the QR code or the 6-character alphanumeric setup code that is printed above or below it. To dismount the doorbell, see the first video in the Help topic below, where it shows mounting and then dismounting the doorbell, starting at about 3:30:
https://support.google.com/googlenest/answer/10732535
As noted in the video, you can use a flathead screwdriver instead of the dismount tool.
Google Nest's doorbells are not designed to be taken apart; I'm not sure how you go about putting the front face back on.
You may also need to perform a factory reset before reinstalling your doorbell:
https://support.google.com/googlenest/answer/9252162
