Conditional logic currently only works on choice fields. I’ve heard some rumors about it possibly adding to things like taxonomy fields but I can’t confirm that. It does not work on the presence or absence of a value in a field. For this you’d need to create you own JavaScript to handle the hiding/showing of a field. There isn’t much in the way of information on how to accomplish something like this. The only information on adding custom JS is here https://www.advancedcustomfields.com/resources/adding-custom-javascript-fields/. I have posted some examples of doing some things with JS here that may get you started on how to detect changes in fields and modify other fields here https://github.com/Hube2/acf-dynamic-ajax-select-example
