Customising homepage

I’m new to WordPress and trying to add a ‘slideshow’ and a brief ‘about’ intro piece to the frontpage in 2 columns and place it above the blog posts and sidebar just like on this site http://www.erlinghamso.no/

How do i add these 2 columns between the header and main content area. I presume I need to add something to the ‘Main Index Template (index.php)’ template in the apporiate place but i’d like to be able to add a ‘page’ so I can edit the text in the CMS.