The crew pool and deck is in the bow area. You can't or should not get to this area. The doors should say either no admittance or crew only. You can see the pool from the forward decks that you get to from the decks with cabins. Usually these are from the Upper deck and up. Start at the upper deck and go all the way forward and then go through the wooden door with the port hole and then out the other door onto the deck.
#12 Carnival cruise coming up Dec 30 on the Valor