Well it is kind of difficult to write a guide for this but I can give you some general advice.
First off, you made it much easier on yourself by not putting the OS on the RAID array. It adds more steps to the install and it is a pain in the butt.
Install Windows on your Raptor [I am assuming you know how to do a clean install of Windows]. Make sure in the BIOS that your Raptor drive is set as the first hard disk to boot from (house keeping measure that reduces boot time by a very small amount).
This step should be done after installing Windows (though it isn't critical):
In order to actually set up the RAID 1 array you will need to enable RAID in the BIOS. I can't tell you exactly where this is but it should be in a section for peripheral devices or advanced configuration or something to that effect. Every BIOS is a bit different. Once that is accomplished you will need to define the array. You will notice that as the computer boots you will see a screen with something to the effect of "Fastrack Raid Controller BIOs blah blah blah" then it should tell you to press "Ctrl + F to define array." Again, the exact message will vary form mobo to mobo, but that is what mine says and should give you a general idea.
Once in the RAID configuration screen you have to define a new array. I can't remember exactly what you press to do this because I haven't dealt with RAID in a year or two. There will be an onscreen guide to assist you, just choose your RAID type (in this case mirroring) and add the two drives. You may have to specify stripe size. In your case I would suggest a larger stripe size of 256 or 512 since you aren't going for max performance and you are dealing with video editing.
At this point you can reboot and load Windows. If you haven't already, you will have to install the RAID drivers in order for windows to properly recognize the array. Then reboot.
I know this is a very rough explanation, but right now it is what I can recall from memory. If I think of anything or if I just confused you, please let me know.