Good question. No there isn't I'm afraid, but the beauty of a forum is that you can always ask. You can try the
General Twinks Section for advice or you can try in the specific bracket sections if there is one you are interested in.
To answer these questions though, a twink is someone who has indeed turned their XP off to PvP at a specific level. Many take the definition further and state that a twink also has the best, or strives for the best, equipment in order to compete to the highest standard.
Level one twinks have never been my cup of tea personally, so you should probably speak to someone else before you make any lasting decisions about the bracket, but as far as I know they generally engage in duelling other level 1 twinks, duelling progressively higher level non-twinked characters (i.e. in levelling gear), grouping up to kill PvE "world bosses" like hogger and going for achievements on the lowest possible character. They cannot join BGs, but world arena such as Gurubashi, Nagrand, Blade's Edge Arenas are all usable if they manage to travel to them.
You turn off your experience by visiting one of the Experience Eliminators -
Behsten for the alliance and
Slahtz for the horde. The guys are actually a testament to twinking and are a rather tasteful joke from the devs since they are dressed (almost) exactly like old school twink rogues did during the Burning Crusade and if you say their names together it sounds like Best In Slots which is a very frequently used term in twinking circles. These guys are found in Ogrimmar and Stormwind where the battlemasters are found, but you have to look carefully since they are stealthed in one of the corners and are hard to find if you dont know where to look. I like to use a "/tar behsten" macro to help me find them. They charge 10g to lock your experience and once locked the experience you would have earned is irretrievably lost, you do not earn it or put it in an experience bank for later or anything, it is simply not awarded. You can then unlock your experience at any time for a further 10g.
The best BG to start in is WSG. This is because it is relatively small and it is the first one you have access to . You also have access to AB, but due to its nature it often not compelling to start in since in the lowest brackets mounts do not exist and thus travelling across the wide map can be frustrating.
Don't worry about feeling intimidated, we have the forums for a reason and we're more than happy to answer your questions.