How to change the view for a rendered product?
You have two high level options: 1) create page templates for your product displays in the theme layer that include the markup your CSS needs to position things or 2) use a module like Panels that lets you build page layouts from within the Drupal admin UI itself. (I'm assuming this is Drupal 7, but if you are on Drupal 8, you should give the core Layout Builder module a try vs. Panels.)