Cannot generate XML for model export from 3DSMAX

Hi guys I am working on a GA airport
I follow the document
https://docs.flightsimulator.com/html/Asset_Creation/3DS_Max_Plugin/Multi-Exporter.htm
to use the multi exporter


But I find that if I hit generate XML nothing happens.
And if I hit Export Ticked there will be a window showing error that XML file cannot be update because it does not exist.

Another question: The document seems not setting a naming convention or folder structure convention. But I heard that you need to put an xxxxxx-modellib inside the Package source folder to store all the folders for models.
Is that true?