冬令營is winter camp. In Taiwan, some organisation or school would held winter camp in winter vacation, which normally in the end of Jan. to early Feb.. Winter camp have different subject; it not only train the students some skill in the wild, but also have some subject, like science winter camp...and so on.
組織(organise) is a verb. it means that get something and someone together to held an activity.
but, In Taiwan, we used to said 舉辦(held)
舉辦冬令營