First generate the DDR from within FMPA. Then click the white "Import New" button at the top of the Home layout, and when it asks you for a file, select the summary.xml file generated previously.

How do I generate the DDR?

Ok, so the first paragraph above made some assumptions about generating the DDR. DDR is short for "Database Design Report". It's a function built in to versions of FileMaker Pro since they introduced FileMaker Developer back with .fp5 files and is now part of "FileMaker Pro Advanced".

To generate the DDR for your solution, open all of the files in FMPA (FileMaker Pro Advanced) and go to the "Tools" menu. From there you've got an option called "Database Design Report...". Select that option. When the dialog comes up, change the radio button from HTML to XML and uncheck the "Automatically open report when done" checkbox. You can leave all of the other checkboxes, the "Available Files" and "Include in Report" options, checked.

It will then ask you for a place to save the file. Leave it named as it suggests "Summary.xml" and save it to a folder somewhere.

You can then close all of the files in your solution and open BaseElements.