Step 1: Register a device
First, click here to check if you have a compatible device. If you see a device under "these devices can get prompts" select the device and follow the instructions. You should see something like this:
If you are able to setup a device as instructed, you're all done, there's no need to do step 2.
If you see no devices please continue to step 2 below.
Step 2: Register SMS & Google Authenticator
If you have no registered devices, click here to register your phone number for SMS or phone call prompts (either is fine but we prefer SMS).
Now, follow the instruction in this article to register the Google Authenticator app as an alternative method. Google Authenticator will provide a more reliable and secure method of authentication.