It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.
You will also need to make sure that you're using oXygen version 20 or later. If you haven't yet upgraded, now's the time. Currently version 20.1 is available.
Download the fop-preview.xconf file: https://drive.google.com/open?id=1k3oRRnzY9Mja6kxpZL-LwF2VfFpoiPSN (save it somewhere that you won't delete, such as your Documents directory; at the Beinecke, you can use the file that's located on the J Drive. A note from Mark: I like to keep my oXygen project file and the fop-preview.xconf file located in the same directory, e.g. "My Documents\oXygen Projects" on Windows)
Make sure that "Use built-in Apache FOP" is selected. Note, you can also change the amount of memory available to your built-in FOP. In the screenshot below, I've changed the memory to "2000", which allows 2 GB of memory to be used during the transformation process.
In the "Configuration File" section, use the directory icon to select the location on your computer where you saved the fop-preview.xconf file.
Download the EAD file from ArchivesSpace, but make sure to select the "EAD3 Schema" option.
Open the file that you just downloaded (usually in your Downloads directory) in oXygen
With the aspace-to-yfad-plus-excel-and-foldering-v2018.xpr oXygen project file open, select "6 ArchivesSpace EAD3 to PDF (preview unpublished)" and transform the file.
If you get an error, email Mark Custer and let him know the Resource record that caused the error.