Godox flashes differ from the camera flashes that we're used to. You don't immediately attach a Godox flash to your camera, as it's mostly intended for use multi-point flash setups. They are true strobist flashes, in an entry-level category. This is why they don't measure the amount of light via TTL (through the lens). Instead, you can adjust the intensity of the flash yourself, via a number of steps. With help of the slave function, the flash will synchronize itself with the master flash, and go off at the same time. With help of the included flash tripod, the slave function can conveniently be used in a strobist setup. This form of lighting is called strobist. Combined with 1 or multiple flashes and accessories such as remote triggers and strobist light shaping tools, you have access to a flexible light setup that lets infinitely experiment.