How to Cook the potatoes in a sauce of herring?

               Potatoes, 2 herrings, one onion, mayonnaise, 0.5 glass of sour cream and mustard to taste. 
           Peel the potatoes, boil. Prepare the sauce: herring clean from the bones, chop, add finely chopped onion and mix with mayonnaise and sour cream to add visual mustard to taste. Serve sauce with potatoes, sprinkle lightly with oil and sprinkled with chopped greens.