the reference_syntax is the path to access to your drop down list
in the example above, to be able to access to DropDownList1 from an event of TextField1, you must specify its path because it is not in the same "parent node / child node" of TextField1
so from any event in TextField1, to access DropDownList1, I must use the reference_syntax below:
So if I understand well, you want to populate the text field's value with yes or no depending the selected value?
You can use this to transfer value to the text field in the calculate event of the text field...
If you want to populate another value than yes or no
Hope this help!