There is a finite amount of room for links on the left-side navigation menu of your website. What do you do when you have more pages in your website than you have room in the navigation menu for links to each of those pages? You create what might be considered a sub-menu or an extension to the left-side menu.
For example, you may want to post your weekly league results to your website. It becomes unwieldy to have 20 weeks (or whatever number) of events listed on your left-side navigation menu. Instead, you can use a List page which acts as an index page - think table of contents - for a topical section of your website content to reduce the items on the navigation menu, yet help people find information quickly. The List page allows you to create a list of links to the various web pages of information such as results for each week of your season as in the example below. If you prefer your list of links to be arranged in more than one column, please refer to "Creating an Index Page Using a Blank Page Template."
For information, please refer to List Page.