When Jacob learned that there was grain in Egypt, he said to his sons, "Why are you staring blankly at each other?
References for Genesis 42:1
I've just heard that there's grain in Egypt. Go down there and buy some for us so that we can survive and not starve to death."
So Joseph's ten brothers went down to buy grain in Egypt.
However, Jacob didn't send Joseph's brother Benjamin along with his brothers because he thought something bad might happen to him.
Israel's sons came to buy grain with others who also came since the famine had spread to the land of Canaan.
As for Joseph, he was the land's governor, and he was the one selling grain to all the land's people. When Joseph's brothers arrived, they bowed down to him, their faces to the ground.