You are the first user to view the file since the file or template was changed.
The system will now look up all of the custom values in the database, and create the new template, header and footer. It will then generate a file which it merges with the original MS Word file and convert everything to a PDF for you.
After the above is complete you or any other person viewing this file will get the PDF instantly until it is either edited again or the template of the file is changed.