Fantasy salad recipe with mayonnaise

We start cooking the potatoes, without peeling, in water with salt and vinegar, so that the skin does not break. They peel tempered, cut into fine slices and place themselves forming a circle in a round fountain. Peel the apple, remove the heart, cut it into segments and spread them with lemon so that they do not get dark. Place them in a circle next to the potatoes. Carefully launch and clean the watercress, placing them in the center of the fountain. Cut the pepper and distribute it between watercress and apples.