This iron is meant for camping food and is buried in a bed of coals. There are still companies which create similar waffle irons, and they offer them in two variations: with long handles for fire/coal, and short handles for stovetop. I have one of these irons in the short handle version.
Of course you can use it inside too. The hinges will obviously be a problem with a contact heating method such as a resistive stove. But gas or induction will work.
You have to first preheat both halves by turning. Then place the dough on the lower, hot plate and close the iron. Bake the lower side, then turn to bake the second side. This method is not as good as the "burry in coals" one, as it doesn't bake both sides at once, so you get a slight texture difference in the sides. But I don't think it is too much of a problem, I enjoy my waffles this way.
If you have never used cast iron, I won't recommend starting with this thing. Start with a pan, which is open, so you have more control over it. If you are accustomed to baking in nonstick pans, controlling the heat and oil amount in cast iron is not easy at the beginning. Also, you will have to season it, and these ridges are harder to get a good seasoning than a flat pan. By the way, once you season it, it will be black and have a slightly greasy feel, so if you plan to use it as decoration, don't start using it for cooking.