Yoooooo
http://clashofclans.wikia.com/wiki/Clan_Wars_FAQ
Here's a nice FAQ about Clan War for our new friends. It's a bit out of date; particularly the bit about how your war village reflects your regular village. That's not the case anymore. Get to that in a sec. Everything else I think applies. When we declare war, it's not our whole clan, it's only those members who want to participate. There is a setting in your profile to 'opt out' of clan war should you want to use it. If you want to see who in the clan is opting in or out of war at any given time, go into the 'My Clan' screen, you'll see all of our names with either a red or green shield around the number ranking. A red shield means that player is currently opting out of war. Not all that important for you guys, but a little FYI.
In the center of your screen, all the way to the right, just above the red head. There is a button with a hand and two arrows. That is the layout editor and you can edit your regular village and war base separately. The main thing to remember is that once preparation day is over, any changes you make to your war base will not take effect until the following war. Any shit you have being upgraded will be available for war at the level it was prior to starting the upgrade.
There is no vegetation or rocks around the war base. Your collectos aren't collecting anything in the war base. Your war castle gets filled upseparately from your clan castle. The troops in the war castle, defend your base during war, they are not used to attack. When attacking during war, you can use the troops in your regular clan castle like usual.
War is like Las Vegas, whatever happens there, stays there. It's like an alternate universe separate from the regular goings on of your village. When battle starts, we can help you select the best opponent and give you some attack strategy tips, so don't worry about that.
As for base design, there are basically two types of bases in clash: farming bases and war/trophy bases. Farming bases are designed to protect your loot. War bases are designed to minimize the number of stars an attacking player can get from you. The most obvious difference is in priority. A war bases prioritizes defense of the Town Hall, a farming base prioritizes defense of loot storage.
Base building tips:
http://forum.supercell.net/showthread.php/220671-A-Beginner-s-guide-to-base-building-The-Dos-and-Don-ts-of-making-a-base(w-pics!)