I added SHA certificate fingerprints in my android app project settings, but I got a warning

It’s true previously I had project have same SHA-1 fingerprint and package name

But I already delete all the previous SHA-1 fingerprint and the same package name in Firebase project, and then start the new one, but still I have that warning

I look at this question and follow the solution in comments but I still didn’t solve it because I didn’t saw any SHA-1 key

and I don’t understand the answer given from that question, where is exactly the location of .keystore and where is the command need to be execute