Most people use a mobile phone as their primary Duo two-factor authentication device. You can however enroll multiple devices to fill this role if desired.
Firstly, you must access your Duo settings by invoking the Duo two-factor authentication system. To do this, simply try to log on to a CSM web service that requires two-factor authentication. For the purposes of this tutorial, I am using https://canvas.mines.edu
After entering your credentials and clicking the Login button, you are redirected to the Duo two-factor authentication page.
At this point your normal process is to select one of the three available options of Send me a push, Call Me, or Enter a Passcode.
As you want to add a new device to your account, instead, select the Settings menu at the upper right-hand corner.
Select Add a new device from the menu.
Duo needs to ensure that it is really you that is trying to add a new device to your account, so you are prompted to authenticate.
Select the method of your choice utilizing your currently enrolled device.
For the purposes of this tutorial I selected Send me a push.
Duo notes that a push has been sent.
After you respond to the push notification on your existing device, the Duo interface asks what type of device you are adding. For the purposes of this tutorial I am adding a tablet computer.
After selecting the device type, scroll down and select Continue.
Select your type of Tablet and click Continue.
You are now prompted to install the Duo two-factor authentication application on your tablet.
Scroll down. Follow the instructions to download and install the application from the Google Play Store or Apple App Store.
Once it is installed, or if you already have it installed, click on the I have Duo Mobile button.
A QR code is displayed on the screen along with the instructions of what to do on your new device.
Launch Duo Mobile on your new device. Click on the + symbol at the top, right-hand corner of the screen.
The display will switch to the camera mode so you can scan the QR code that is on the computer screen.
If the QR code scan is successful, the QR code fades and has a green check mark superimposed on it.
Scroll down a bit and click on the Continue button.
You'll now see your new device listed underneath your existing device.
Scroll down a bit and click on the Continue to Login button.
You're now returned to the main authentication screen. The drop-down box under the Device heading now has your default device listed.
If you want the system to utilize your newly enabled device, select it from the drop-down list.
You now select the authentication method of your choice. Note that in our example, there is no longer a Call Me option.
This is because the tablet computer just added does not have telephone capability.
Select Send me a Push.
After you Allow the push on the new device, you are logged on to the web site.
The process is now completed and you can use either of your registered devices to authenticate.