A question for sims 2 castaway how do i get into geyser rock i know i need a chisel and an hammer to inspect it but i need to make a forge to build it on and i dont know how to make a forge help?

You need to find the llama temple. An in the middle of the room, near the thrones you will find the forge. Then go to the forge and it will say 'repair' or 'build' or whatever. An then you can make new items and stuff.