The basic rules set for fantasy is a little more complicated than that of 40k, but after a few games you should have the hand of it. Now with all the little 40k additions, there are a lot less rules in fantasy.
The Dark elves themeselves are a whole lot manueverable than the rest of fantasy races, sans the skaven, with a base infantry of 5....which really is a huge advantage as you will come to realize. The dark elves themselves are very delicate, particularly their characters who are only toughness 3, which is very low, but they have unbeleivable leadership. Damn elves. Their sorcerresses get +1 to cast spells, again a massive advantage, and have access to some very potnt magic items. The core units of the dark elves are Dark riders, corsairs, and warriors. For block infantry I suggest the corsairs, for archer support take warriors with repeater crossbows (a very nasty piece of kit), and the ever useful dark riders. Basicaly if you keep in mind that you are faster, have better missile options, you should be fine. Just remember to avoid head on fights...Dark elves can take damage about as well as Eldar can.:flip::bouncy: