The setting is the physical place where your story will be taking place. If you are writing about a setting that you are unfamiliar with then research it. The setting of my series is the desert. Having never been to a desert before I had to research what the Kalahari Desert is like and the flora and fauna that live there. I have to be aware of its special characteristics in order to portray it plausibly. You should do the same with your setting.
Right now we are just addressing the basic, all-encompassing setting. My setting is the desert but more specifically Alpha territory. You can take your general setting and narrow it down by making a list of where events in your novel will take place. This will help you organize the locations for specific scenes in your novel later.
Why should you determine your novel’s setting so early on in this process? Many things can be affected by your setting. If your story takes place in the royal halls of England and mine the Wild West then they are going to have two distinct voices because of the difference in setting as well as the difference of authors. Think of all of this as you determine your setting and start writing the beginning scenes of your novel. Remember that setting affects tone and voice, so before you start writing make sure everything setting-wise is plausible. For a novel taking place in Florida you may not want to emphasize how the bitter cold has chilled the hearts of the residents of that state. Catch my drift? Always make sure that your setting, well, makes sense.