adding a banner
It does rather depend on how your site's theme is set up. Sometimes there is a full width banner area at the top of the page. If there isn't you may find that you can add a layout to the top most area, and use the block's settings menu to disable the Block Container Class . This will allow the block to use the full width of the page.
You would need to add a block to the area. You could use an image block, or the image slider block. Both of these would work.
If adding blocks or layouts doesn't make any sense, you might want to checkout the user guidehttps://documentation.concrete5.org/user-guide...