If the user tries to go a page on your site that does not exist then Genesis sends you to what is known as the 404 page. This page displays a “Page Not Found” message.
On Genesis HTML5 sites the page also has a site search box, on non HTML5 sites in contains a site map of pages, categories, authors, recent posts, etc.
But what if want something else on the page?
With the Genesis Club Pro Plugin you can choose an alternative page as your 404 page. All you need to do is create that page as a standard page and then select it in the Display section of the plugin.