General agreements about what is good and bad, what is right and wrong, what is desirable and undesirable. Through living together they have come up with their own unique way of doing things and getting things done that need to be done for these people to survive. How to get food, how to get shelter, how to make clothes, etc. They have come up with their own methods and tools. Their own understanding of how the world works.
Every society has a body of knowledge what they have learned and understand about the world.
They have come with rules about how to behave, rules that guide interaction with each other. And because they know what is expected of them and what to expect from others in the course of their daily lives as they go about their business there is order and not chaos. They have interacted long enough together to have developed and passed on their own customs, habits, traditions. Their own kind of music and art and religion. Their own ideas about what is beautiful.