how i can go underground?

[hss24]

I cant craft a stone stair ...no craft icon in the craft table or forge !!!. Only the copper and iron stairs !!! I could not find any lamp copper on the map. How can I go underground ????
did i miss something ??

[Naloth]

This is one of the changes since the last update. You first need to beat the Air Dungeon in order to go to the next layer. In the last release the first dungeon was underground. You couldn't reach the second underground layer until you beat the first dungeon. Since the first dungeon is now above ground you need to beat that first.
To get to the first dungeon follow your tin compass.