My goodness, you've taken on quite the task for someone that has never built before. You're in for a bit of a challenge, but I guess you know that already don't you?
In this guide, you'll see where to find the XMP setting:
http://rog.asus.com/forum/showthread.php?5836-ASUS-Rampage-IV-Extreme-Easy-Overclock-Guide&country=&status=
Set XMP, BUT set the memory divider ratio to 1333 manually for now. I suggest that for now because, you're starting out and dont want to be fooling with an unstable system right off the bat. Don't follow the rest of that guide for the other overclock settings. I've just linked you to that so you can see where the XMP setting is.
You may need to update UEFI to the latest version. Depending on which version your board shipped with, you may need this guide here:
http://event.asus.com/2012/mb/USB_BIOS_Flashback_GUIDE/
If you already have .CAP BIOS then you won't need to do the conversion. You need the latest BIOS to follow the guide below for RAID as well (early builds don't have the UEFI RAID Driver built in).
For RAID, I suggest you follow this guide here:
http://rog.asus.com/forum/showthread.php?30520-RAMPAGE-Windows-8-7-UEFI-Installation-Guide&country=&status=
-Raja