The steps in the resolution describe how to export Emails as XML and import the result into HEAT with .xslt
Instructions on Exporting the email from the email listener as xml can be found in the Help. a search on xml Export returns:
Key here is specifying the folder location to which the files are written within the email config within ConfigDb.
Once you are exporting the xml to the directory defined in the email configuration workspace in the ConfigDB, you will need to set up your Data Import Connection with the .xslt: