There are two spots where you can see the silos. To see the first one, follow the previous path. That is the path you see when you go through the entrance of the castle. Go straight through the marked trail. Following the second circle of walls, you will to market spot where the first silos are. They should be on your left. The second set of silos are inside the castle, which is in the paid zone. To find them, walk to the entrance where the ticket machines are. From there turn left and find the bathrooms and cafeteria. Then find stairs on the left corner heading downwards. This is the archaeological area. Inside, simply look down to see the second set of silos.