How to add key from Git bash console?

Question

git

Installed Git Bash for Windows https://git-for-windows.github.io Generated keys in Putty Key Generator and added it to my
Github account
Access
Full error text:
The authenticity of host 'github.com (192.30.253.112)' can't be established.
RSA key fingerprint is SHA256:nThbdsfgJfWGl7E1IGOCspRomTdCARLviKw6E5SY8
The old key to the old account may be displayed in the error text, I need to replace it with a new one, but I can’t understand where and how