You visit the “Futures Market” category and click on the wrench icon to edit the category settings.
There you will find the settings ondrej and I mentioned.
There is also a topic about the Available settings within the category edit page and a guide especially about how to Display boxes for subcategories above topic list.
The category banner is added by a theme component. If you need further information about how to install it, you will find a guide linked in the table at the top of that topic.
To configure the default categories in the sidebar, you have to change the default_navigation_menu_categories site setting. You can search for that in the admin area of your forum.