iTunes Windows ver. - where do I enter the validation code

When logging in with my apple account and password, it sends a verification code to my devices. iTunes for windows simply wants me to log in again and when I enter my password it says I forgot it and there is never a following window to enter the verification code. Are we supposed to enter our password AND the verification code all in the same entry with no space between our pw and the code? If so, that is the most user unfriendly thing I have ever seen Apple code.