A CMS page can be created using existing file (pdf/mp4/doc).
Create a CMS page:
Enter page name and enter some text in content area ( As page content is mandatory) though in show file mode page content will not be displayed.
Upload the file
Using paper-pin icon upload the pdf/doc/mp4 file that you want to show as page content then save and publish the page. [Upload one file only]
CMS page properties :
Access page properties and enable 'Show File' property. Save/Publish the page.
Page view ( Uploaded pdf file)
CMS page can be added as part of the knowledge-base.
NOTE: If page name is given with file extension then there is no need to enable 'Show file' property.