You manipulate the stars, and change constellations to affect people’s horoscopes, navigational systems, bird migration patterns, whatever else stars affect, and all in all the general aesthetic of the night sky. Thus you change the course of history and the world.
It would be like one of those God Simulator ones, except you cannot directly affect the planet. You can only really confuse the planet.
The Sun also counts as a star. So you could like just blow that up or whatever too if you wanted I guess. A quick ending. Good job.