1. Upload the PDF to your box.com account ( see link above ) ( create a new folder like the one I've created below)
Once the file is uploaded and you see it. Then goto the sharing tool on the right side.Click Share Link.
Then click on the Advanced Settings:
Copy the Allow Download URL. ( You can add a custom name to the top )
Paste that URL in the CMS editor for the Office Property on your web site.
You can also use that URL for any public web site to allow direct download access.