I am trying to create a sample page which has the same formatting as the default home page e.g. with 2 columns. I know how to use short codes eg featured items. But I can't format the page.
Also I'd like to remove the black line under the banner
It will vary a little bit based on the theme you are using. What's the theme you are working from?
Chances are, you'll be able to modify the
index.php file from your theme to make it the structure you want for the simple page. That would call for overriding the simple pages