Sign in with your current password, then choose a new one.
Enter the 6-digit code from your authenticator app.
Enter one of the recovery codes you saved when you set up your authenticator. It works once, and you will set up a new authenticator right after.
If you lose your phone, any one of these signs you in once. Keep them somewhere safe; they are not shown again.
You signed in with the shared starter password. Set your own to continue.