PDF Link
Instead of embedding the document you can insert a link to it as shown here.
Get the link to the file, like https://drive.google.com/file/d/0B28Gtf1n8u8DSUd0VVdUNENRaWc/view?usp=sharing
In a text box put the text you want, like "PDF File".
Highlight the text, click the link icon and insert the link to the file.
To download this file click the link above and then click the download icon on the result.
See this page also
You can also use an image as a link. Insert image, click it and use the link option in the edit area.