Don't worry about where you are coming from, think about where you are going TO. And every flight has a number - it's on your tickets. Walk into the airport and all over the place are big, digital boards that list all flights. One is arrivals and one is departures. Look at departures, find your flight number and the city you are going to - even if it's just one leg, you are going to that city. And the gate number - where the plane is. Go to the gate and get on the plane. Next airport, if necessary, do it all over again. You'll get on the plane to Atlanta, and then the plane to Denver, and then the plane to LA, and then finally to your destination in Las Vegas. Like that.