Actually I might just explain it anyway for anyone else who might not know either in case they're reading this.
So you know how people can see shapes and stuff in clouds, right? Well, imagine the same thing here, but in how the stars are arranged! And then people made up stories about how that set of stars looks like a cool dude and the set next to it looks like a snake or dragon or something.
Anyway a sign is based on which one of the biggest, most well known constellations was overhead when you were born.
2/2
So you know how people can see shapes and stuff in clouds, right? Well, imagine the same thing here, but in how the stars are arranged! And then people made up stories about how that set of stars looks like a cool dude and the set next to it looks like a snake or dragon or something.
Anyway a sign is based on which one of the biggest, most well known constellations was overhead when you were born.