The Decorus format works by them sending the XML file and any associated media to your server via FTP.
As a result you'll need to create an FTP user on your server for them to use. We also recommend creating a separate directory for them to put files into to keep the uploaded files separate from your other site files.
From within Decorus an export can be created and these options entered:
Here you can enter the details of the FTP user you've created. For the 'Image Path', 'Data Path' and 'Document Path' these should all be the same as we require all files be put into the same directory.
When creating the import in Property Hive, simply enter the path to the folder where the files are going to be uploaded to: