What does 1 Samuel 16:1 mean?

God said to Samuel, 'How long are you going to keep grieving over Saul? I’ve rejected him as king. Fill your horn with oil and go. I’m sending you to Jesse in Bethlehem, because I’ve picked one of his sons to be king.' 1 Samuel 16:1 - Modern Text Bible

(God tells Samuel it’s time to move on from Saul and start something new. He’s chosen someone else, and Samuel’s job is to anoint the next king.)