I am pleased to see both coarse thread and fine thread bags of thumbscrews. Honestly, there's thirty of each, so use them as needed; there are enough to go around. In front of both bags there are seven threaded rods. These act as expansion card supports. One end screws into the motherboard tray while the opposing end accepts the fine threaded thumbscrews for securing the card in place.
Here is what Microcool calls the "fan door hanger". It is a thin piece of the same material as the rest of the Banchetto. Facing you is a wire management hole that matches one in the tray. Simply use two thumbscrews and mount it in place. While I didn't mount any 92mm fans myself, asking a friend who owns one, he said his piece snapped in half when mounting fans. Honestly, I would rather this piece be anodized aluminum anyways, that would solve that issue.