The above instructions are not complete. These are the full instructions that work for me:

1.Before you turn your phone off, go to the developer options and enable USB debugging.

Go to: Settings, About phone then tap Build number 7 times.

2. Go here Get the Google USB Driver | Android Developers and download the google USB zip file (this is for windows BTW)

3. Unzip however you want it

4. Open the folder usb_Driver and rightclick "android_winusb" and install

5. To make sure it installed, connect your pixel (with USB debugging still enabled) to your PC and open "device manager". You should see "Android Devices > Android Composite ADB Interface".

6. Disconnect pixel from PC

7. Go here Google Fingerprint Calibration website and follow the instructions.

https://pixelrepair.withgoogle.com/udfps