I don't get PAL's Fly All You Can promo

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I'm looking for a good fare deal for a Hongkong trip late this year, and I came accross PAL's Fly All You Can. I think their website is too cluttered and its hard to understand where to go to check for booking availability or to find out more about that promo. I just don't understand how it really works. It sounds interesting but Im sure there's a catch. Can anyone help me understand this better?