The first batch of items to upload was the letters, but two more columns needed to be added to the spreadsheet first.  The first new column was for tags:  all of the theme and subcategories contained in the letter as identified during the tagging process.  

The second column was for a link to each letter’s PDF file.  This link was created by using the Dropbox plugin for Omeka (not to be confused with the commercial file storage site of the same name.)  Dropbox creates a web folder where files can be accessed during bulk import.  PDF documents of the transcribed letters were added to the Dropbox web folder.  These URLs were copied and added to the spreadsheet in a column called “links.”