How to make horizontal a vertical sidebar?

Hello,
following this tutorial: http://appointzilla.com/how-to-add-more-sidebars-in-a-wordpress-theme/ I’ve created a new sidebar for adding widgets; the only thing that does not work is the alignement; I need it to be horizontal. I wonder if there is something in the simplebright theme (the one I’ve installed) that stops to make it horizontal.
Here is what I get:
Thank you for any help.