Well, it's not for sure yet, but they're going to see if this plan works. The basics are illustrated here (click so you can see it full size, if you're interested).
By the way, isn't it amazing what Kepler has done regarding the prospects for life (maybe even intelligent life) elsewhere in the galaxy and Universe? It used to be one big unknown was if other stars had planets. Now it seems that the odds that a star doesn't have planets of some kind are higher than the odds a star will have planets of some kind.