The large lanterns can take a while to light, and when they are released, they float slowly upwards into the sky. At one point, there will be thousands of lanterns floating up, and hundreds of people moved to tears on the grounds below. It’s a truly beautiful sight to witness. The lantern, if it disappears into the night, before the flame burns out, is said to erase a person’s bad luck. I think being able to witness this event, let alone participate in it, is evidence that the person has good luck.
Although the main event takes place at night, most of the photos can be taken with handheld cameras. There is quite a lot of ambient light in the area, and shooting with a high ISO should allow you to take great photos. You can improve the quality of the images by underexposing the shots, so the blacks remain black, and the bright flames of the lanterns are not blown out.
In general, you’d want to keep your shutter speeds reasonably high, so that the lanterns are not blurry as they rise (unless that’s what you want to do). Using higher ISO’s would make this happen. For blurry/artistic images, or if you’re using long lenses, a tripod would come in handy. The venue does not ban tripods, so feel free to bring yours.