When Jacob heard that there was grain available in Egypt, he said to his sons, "Why are you standing around looking at one another?
I have heard there is grain in Egypt. Go down and buy some for us before we all starve to death."
So Joseph's ten older brothers went down to Egypt to buy grain.
Jacob wouldn't let Joseph's younger brother, Benjamin, go with them, however, for fear some harm might come to him.
So Jacob's sons arrived in Egypt along with others to buy food, for the famine had reached Canaan as well.
References for Genesis 42:5
Since Joseph was governor of all Egypt and in charge of the sale of the grain, it was to him that his brothers came. They bowed low before him, with their faces to the ground.