At work I always forget this so this is a technical note for myself. Maybe it will help you too?

• Run lspci to determine what controller you have.
• Visit the nVidia driver website and select your controller.
• Stop X (telinit 3)
• Download the file and chmod 500.
• Verify you have gcc and kernel-devel packages installed.
• Execute the program you downloaded from nVidia.
• Start X (telinit 5)
• Log in
• Execute nvidia-settings
• Activate additional monitor (twinview)
• May have to enable Xinerama for more than two monitors.
• Enjoy fruits of labor.