To protect your Google account with a FIDO/U2F security key, first you need to use a browser that supports U2F such as the latest versions of Chrome, Edge and Firefox.
To turn on 2-Step Verification, follow steps below.
Sign in your Google Account
On the left navigation panel, click Security.
On the Signing in to Google panel, click 2-Step Verification.
Click the GET STARTED button
Click Choose another option
Click Security Key under Choose another option
Have your key ready, but not connected to your computer. click Next
Now, insert your key
Touch the key. You will see a popup window below
Click the Allow button
Your key is registered. It is recommended that you name the key, which will be very useful if you are going to register multiple keys in your account.
Enter the name of the key, e.g. Deepnet SafeKey, click the DONE button to finish.
Enter your email address and password, click Next
Touch the key