My Granny used to make butter and she used a churn to make it. She started by taking the cream off the milk. That was left overnight after the cows were milked. Then the cream was poured into the churn. She churned for ten or fifteen minutes.
By then the cream had separated into a milky liquid and little blobs of butter appeared. Then she removed these pieces from the churn and put them in a sieve. Next she poured the liquid from the churn into the sieve. The liquid is called buttermilk and is used for baking.
Next she ran the butter under a cold water tap. Then she kneaded it with salt. That’s how my Granny made butter.