In Blogger Template Designer, you can change the template layout easily. Various layouts have been provided and been able to choose. Just by clicks, you can change the layout of your blogs’s template.
What can you do with Layout menu in Template Designer? You can choose the two-columns layout, three-columns layout and so on, left-sidebar layout, right-sidebar layout, add footer, rearrange the width, and more

Read more - http://havelockknights.blogspot.com/2011/06/blogger-tutorial-change-layout-with.html