To find these settings go to:  Admin  >  Settings  >  Products  >  Categories
The image below displays where to find categories as well as highlighting the two settings mentioned above.

The first setting, Category Display Type, has three options available to use. Below will be examples demonstrating how each looks when applied to your web page.

Original is great for grabbing customer's attention with larger images being displayed. This is handy if you don't have a large variety of items and wanting to fill in space.

Grid allows for a more structured look adding lines in between the images as well as condensing them down allowing for more categories to fit on the page and allowing for subcategories to display.  This is great for situations in which you'd want to display as many products as possible while maintaining a professional look.

Tiles allow for the viewing of sub-categories to be viewable underneath the category itself. This allows for easier and more intuitive navigation on the site.  Great for those who may have a large number of sub-categories for their items who want to offer a quicker way for their customers to navigate with.

The "Hide Left Nav for Categories" setting allows you to remove the navigation menu on the left side of the site when only displaying a category page. You can see this demonstrated in the image below.