Hi,
Your screen capture shows that there are indeed logs in the /var/log/asterisk directory so I am not sure why you say that there are not any...
That said, have you followed the steps provided by Joel Snyder in the comments section of http://wiki.freepbx.org/display/FOP/Installing+FreePBX+12+on+CentOS+6.51 (ie the URL YOU provided).
The tutorial you followed has steps missings and Joel tells you what to do in the comments section.
Good luck and have a nice day,
Nick