Drizzle some oil on the bread slices. Sprinkle with salt and pepper. If your bread is fresh, toast or grill it it to provide a sturdy canvass for your toppings.
Arrange the bread on a dish or platter, depending on if it's a main course or appetizer.
Scatter the mozzarella, tomatoes, and basil over the bread. Drizzle the oil on top. Season with salt and pepper. Give a few shakes of vinegar.
Let sit for at least 10 minutes, and up to 30 minutes before serving.