At the time of writing this article, Dark And Darker Gold is not yet available on Steam. However, the developers might release a demo or playtest version in the future. If they do, you can download the demo by clicking the "Download Demo" button on the game's store page. The demo should be a smaller version of the game that allows you to try out some of its features and gameplay mechanics.
Once you have downloaded the Dark and Darker demo, you can launch it by going to your Steam library and clicking on the game's icon. The game should start, and you should be able to see the main menu. From there, you can choose to start a new game or continue an existing one if you have played the demo before.
Dark and Darker is a horror game that takes place in a dark and creepy environment. The game features different enemies and obstacles that you need to avoid or overcome. You can use various tools and weapons to defend yourself and progress through the game. The demo version might not have all the features and content of the full game, but it should give you a good idea of cheapest Dark And Darker Gold what the game is like.