Boil potatoes as jacket potatoes for 20 minutes. Dice the onion. Cook with the broth for 1-2 minutes, then add the vinegar, salt, pepper and sugar and season to taste. Peel and finely dice the apple and add to the hot dressing. Peel the potatoes, cut them into slices, pour the dressing over them and refrigerate for 1 hour. Then cut the cucumber into thin slices, cut the chives into rings and stir in.