Well I didn’t so I went on a hunt to learn how.  I took me a bit to figure it out but now, in hindsight, it’s not so hard.

  1. Place your cursor at the point in your post where the link should appear.
  2. Click on Add media from the top of your post window.
  3. From the Your Computer section click Browse, choose the file then click Upload.  
    NOTE:  from what I can tell you can only upload PDF files.  I was unsuccessful with .doc, .xls, .ppt and .rtf files.
  4. When it uploads a form will display.  Click Insert into Post at the bottom of the form.

Example:  nets-for-teachers-20081