Keurig Elite K45 reservoir parts not assembled?

The reservoir came with 4 pieces inside it: a disc (size of a checker piece), a spring, a silver metal piece and a plastic piece which looks like a mini tower. I can't find any mention of these parts in the instructions/owner manual or online at their website. These were not assembled (I'm guessing they usually come assembled). I believe the filter will connect with these pieces once they are assembled. Does anyone have information about them?