Install-pdf not work with asterisk

Hi, with the fax function work with pure freepbx +asterisk. I followed the following link as:

it says I need to install fax-to-PDF conversion tools, but the command for install-pdf not worked for the server I have, any one know how to manually install pdf conversion tools?

I have been suffering in fax with asterisk server for so long time, any one has a complete link with all the configuration and bugs for fax with * server??

thanks in advance.

There is a little more to it than that on a self install

yum -y install ghostscript