You don't have to build the Golden Gate Bridge to go from San Francisco to the North Bay. It is already there. So, when you create Web pages, why take the time to build them from scratch when the basic structures or layouts for many Web pages are available for the taking. Can be derived from other Web pages.
Templates are everywhere.
If you like the way a Web page is laid out, why not uses it as a template for your own Web page. There is nothing wrong with using the structural elements of somebody else's Web page. This will bring up the page composer window. You will be told that you have to save the Web page and images. Create a folder to save the Web page and images to.