The Get Mail action has an optional input called Attachment Directory. If the input is used and the mail has attachments, they will be read into the directory. So the steps would be;
- Delete/Move any old files from folder
- Get Mail
- Check folder for PDF files
- Move PDFs away from folder
- Delete any remaining files in folder
It's been a while since I used Mapiex but I recall having to add delays into BP to accommodate the time taken to download attachments - if they are large files then they won't be instantly available.