Logging in to Windows with fingerprint is a simple process. On the login UI, select "Fingerprint" as the 2nd authentication method:
Then, just swipe or scan your finger on the fingerprint reader or scanner.
If PIN is required, then you'll be prompted to enter your PIN:
If this is the first time you're using fingerprinting, and your fingerprint policy requires that a newly enrolled fingerprint must be activated first, then you will be promoted to activate your fingerprint:
That's it. if your fingerprint is right then you'll be allowed to login straight away.