No: it should ājust work.ā
PhotoStructure may need to be granted read access to your Photos library (via macOSās permissions-by-app system). macOS is supposed to pop up a dialog saying āare you OK with PhotoStructure reading your Photos?ā, but in practice, rendering this dialog is unfortunately hit-or-miss.
These settings can be checked (on Mojave, at least) via System Preferences > Security & Privacy > Privacy, and adding PhotoStructure to either the āPhotosā or āFull Disk Accessā sections.
(In general, itās a good security practice to only give an app the minimal permissions it needs to do work, so just giving access to Photos should be sufficient for PhotoStructure)