If we’re using a sun unlike Earth’s yellow star, we’ll need to start there because this impacts much about our world, but otherwise little is dependent on another subject from a world building standpoint. Our biggest decision beside sun type is whether our world has a moon and how many. It’s recommended to have at least one unless we’re certain of what we’re doing without one, because the absence of a moon will cause more changes than we might be aware of. The world’s going to have an equator, prevailing winds, climates, constellations visible, and possibly other planets in the system, but none of these affect us until we start creating continents. Enjoy the rare privilege to embark on a world building subject in whichever order pleases you.