Go through the Arizona state interview until you encounter the screen entitled "Contributions, Tuition and Fees Paid to Qualifying Schools". Check the box next to "I made contributions to a private qualified school tuition organization by April 17, 2018 (not already claimed on my 2016 return), I wish to include on my 2017 return." (I agree this wording can be confusing).
This will give you two more screens as you continue on which you can enter the organization's name address, and the amount you contributed.
