The Galaxy A12 is a low-end slate Android smartphone released by Samsung in November 2020 as a successor to the Samsung Galaxy A11. Identifiable by model number SM-A125 (followed by version/carrier-specific character.
Make sure your phone is definitely an A12 (A125) and not an A12 Nacho (A127). They have two different screens so if you are using the wrong one it will not work.