Slice, quarter or halve the tomatoes, based on your preferred salad presentation.
Slice, quarter or leave the mozzarella whole, again based on you would like to assemble the salad.
For a caprese salad platter:
Arrange the salad on a large platter; you can use one or two platters depending on the size. If using slices, you can add the tomato slices first and then either add the mozzarella slices on top, or stack them alternating the cheese and tomato slices in a slightly diagonal way. For a rectangular or square platter, you can create straight horizontal layers, and for a round platter you can form round spiral like layers.
You can also place the mozzarella, whole or quartered, in the center of the platter, and arrange the tomatoes, sliced or quartered, around the cheese.