Make a connection to your server using an FTP tool
and upload the file into the folder named wscxxxxxxxxx (x being a digit).
After uploading the file, open WSC editor. Navigate to the page where you want to insert the link.
Type the text for the link. For eg: "Click here for document"
Highlight the text. Click Edit-> Link
Select External link and type in the full link, such as http://yourdomainname/file.pdf