Add Phone to Duo with Chrome Touch ID

If you setup Duo to use Touch ID in the Chrome web browser, you will need to add a second authentication method.

Add a phone number and the Duo Mobile app

On your laptop in Chrome, open an incognito window.
Go to any Swarthmore service that requires sign in like http://linkedin.swarthmore.edu/ or gmail.swarthmore.edu.
Stop at the Duo screen.
Click Other options
Click Manage devices at the bottom of the device list.
Authenticate with Touch ID.
Once you authenticate with your fingerprint, you will then see the option to Add a device.
Add a phone number and Duo Mobile.
Follow the prompts to complete registration.
Afterwards, login with the new method to test it.