I am trying to set up an AMD W7100 graphics card on a system running RHEL 7.1.

I am unable to make use of the AMD GUI (amdcccle) to setup the monitors. As such I am into the dark art of to editing the xorg.conf

The card has 4X output ports (0-3):

Port 1 to mirror port 0
Port 3 to mirror port 2

The desktop is to be spread out over ports 0 (right monitor) and 2 (left monitor).

My questions:

1. What is the best resource for descriptions on how to effectively edit xorg.conf?
2. Can someone provide an example xorg.conf with a single card 4 port setup?