How to Install second VGA ?

i am going to use three monitor but i dont know exactly how
take a look here http://www.kegetys.net/SoftTH/

SoftTH allows using three monitor "triplehead" with Direct3D 8 and 9 games without special hardware. You need three monitors attached to PCI Express video cards. Only one card does all the rendering work, so secondary card can be a low end card, only Direct3D support is required.

now i have XFX 9800 GTX black editon installed
and i have one extra VGA WinFast PX6600
should i install driver for second VGA when i pluged it in ?
one of my friend said i need to change some option in BIOS what are does ?
my motherboard dont have any onboard VGA
could u explain for me ?

this is example of this website.
GeForce 8800GTS 512MB PCI-e 2.0 (Rendering, middle monitor and right monitor)
GeForce 8400GS PCI-e (Left monitor)

i have4GB ram 780w power CPU core2quad .....

GA-EP45-DS4P
http://www.gigabyte.com.tw/Product [...] uctID=2839
look At pic too

could u please Tell me what should i do after plug in the second VGA ?then what should i do ?some change in bios ?whats that ?then what install driver for second vga ?it wont damage windows and ...?then plug 3third monitor in that vga ?