Hi Applemint,
May I inquire where you intend to import the PDF? Are you doing this through code or via an end-user application? You can readily import your PDF using the ‘document uploader’ display feature in your end-user application.
As shown in the image above, after clicking the upload button on the document uploader, a dialogue box should appear, allowing you to import PDFs from your network drive.
Please follow these detailed steps as a guide that have been provided in a previous answer
How to Store Document like Pdf in five? - How do I? - Five Community Forums