Does anyone know where to use the Setup Device verification code in the app?

[Moab]

I set up a device on the website and was given a verification code for my mobile device. I can't figure out where to use it on the device. Instructions indicate it must be used within 2 days. 

[VanKalkerFarms]

When you open the app it defaults to using an email address and password.  On that same screen, there is the option to click to sign in using "Use a device code".