In this tutorial i will teach you how to create a 3 column blogger template with two narrow columns on the right and a section above the two columns here's a simple screenshot of the layout I'm planning to teach you to build

1. .Log in to your dashboard--> layout- -> Edit HTML

2. .Click on "Expand Widget Templates"

3. Search (CTRL + F)

body#layout .art-sidebar1{          

 width: 25%;        

 }

4. After this line add:

#sidebar-top{
clear:both;

}

#sidebar-right{
width:50%;
float:right;
word-wrap:break-word;
overflow:hidden;

}

#sidebar-left{
width:50%;
float:left;
word-wrap:break-word;
overflow:hidden;

}

5. Now look for:

<b:section class='art-layout-cell art-sidebar1' id='sidebar1' preferred='yes'>

6. Change : id='sidebar1' to id='sidebar-right' and 'art-layout-cell art-sidebar1' to 'sidebar' and paste the folowing lines : 

<b:section class='sidebar' id='sidebar-top'/>
<b:section class='sidebar' id='sidebar-left'/>

before:

<b:section class='sidebar' id='sidebar-right' preferred='yes'>

7. Save your template and you are done.

IMPORTANT
THIS TRICK WORK ONLY WITH TEMPLATES MADE BY ARTISTEER 2.4 AND 2.5 VERSIONS.