Developer here (I'd like to say designer but I get stuck with the code work either way).
As part of a much larger system I have built a system to sign up for a course.
A user can land on this page having pre-selected a course or a course and a place. I need to ensure the user has selected all three but they need to be selected in the order left to right. Selecting a new option from any box resets all the options to the right of it. I want to make the experience more obvious and intuitive without altering the basic 3 field structure too much. So far my ideas revolve around using colours, more text and icons but I also want to keep it as light as possible.