Prawn Nicoise salad

Toss together 1 cooked, diced medium potato, 1 boiled egg, ½ cup steamed, sliced green beans, 1 cup butter lettuce leaves, 6 halved cherry tomatoes, 6 cooked, peeled king prawns, 6 black olives in brine, 1 tsp olive oil and 1 tbs lemon juice.