Assuming you are referring to the popular Star Wars Death Star Waffle Maker, the short answer is about 5 minutes.
To get a little more specific, it is recommended that you preheat your waffle maker for at least 3 minutes before adding your batter. For best results, use a light and airy batter - something similar to what you would use for pancakes.
Once your waffle maker is heated and ready, pour in your batter and close the lid. Cook for about 5 minutes or until golden brown.
For extra fun (and if you're feeling ambitious), try using cookie cutters to create shapes out of your waffles before cooking them. Just be sure to lightly grease both the cutter and the waffle iron surface beforehand!