When you apply the product.details template to one or more of you products, you will have some additional settings available when you navigate to this product in the theme editor. You can then add content below your main product area, such as a Rich text and image section like this one. Other optional sections include an Image gallery (3 photos per row), a full-width Image with text overlay , or an Image with text which has text on one side and an image on the other. You can even control the spacing between all these additional content blocks by adding a "divider" section!