-(으)면 sets a condition and 원하다 'want' follows, almost always as 원하는 plus a noun — 'the one you want': 맞히면 원하는 멤버와 점수 교환, 'guess right and swap points with whichever member you like'. 원하다 is a slightly formal 'want' for things and outcomes; for wanting to do something you would hear -고 싶다 instead. Two lines here are just the word 아니면 'or', where the -면 is not a real condition.