(1) The room is very small as expected, but if you really need to lie down and have a few hours of sleep before the next fly, it is absolutely good choice. If you feel cold, you can always ask the staff for a blanket.
(2) It was very quiet during my stay. Bear in mind to move quietly, close the door lightly and speak softly as not to disturb others. Then everyone will have a good sleep.
(3) The staff at the reception was very helpful and cheerful while the staff at the sleeping area was a bit cool and did not talk much. I suppose it was because he tried to keep as quiet as possible; perhaps some smile and kind gestures may help avoid unnecessary misunderstanding.
(4) The reception is right beside C14. As the airport is really very large, it will take rather a long walk to get to the reception. The sleeping area is hidden behind the duty free shops downstairs. After checking in at the reception, turn around to C16, turn left and go downstairs to the duty free shop area. Turn left to the cosmetics shop, but do not go into the shop. Instead, turn left again, then turn right and you will see a small logo "sleep 'n fly". Inside is the sleeping area while there are public toilets and a drinking water dispenser on the other side.