In Minecraft I have a 27 block wide...

In Minecraft I have a 27 block wide 12 block tall 18 block deep rounded off natural looking cave mined out of the side of a massive mountain with a lake at the bottom and more mountain going around in like a c shape, can you give me a step by step guide with pictures for an amazing house in the mountain or on it or something like that Make it rustic mountain like home hanging off the cliff