Create a three column Blogger template

Learning blogger template is not too difficult. I suggest you to start it using The Minima template. The Minima template is the easiest Blogger template to customize, as this is the simplest two column template, and has few parameters regarding margins, padding and the like.

This article will explain you an example, how to create a three column template in Blogger layouts, using the Minima template as a starting point.

To get this template, first you have to set your template to Minima (not the stretch template, but any color will do!), then follow these instructions:

1. Go to Template>Edit HTML, leaving the "Expand widget templates" box unchecked.
2. 
   
3. Now, find this section in the HTML code:
   
   #sidebar-wrapper { width: 220px; float: right; word-wrap: break-word; /* fix for long text breaking sidebar float in IE */ overflow: hidden; /* fix for long non-text content breaking IE sidebar float */ }
   
   Copy and paste this entire section directly below. We're going to change the elements I've highlighted in red to the following:
   
   #left-sidebar-wrapper (this makes the css for this section unique) float: left (this will make the new sidebar float to the left of the main column)
   
   This will provide the styling for the new sidebar element which we will create next.
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5. Now, you need to find this section further down the page:
   
   <div id='main-wrapper'>
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7. Immedietly before this section, you should paste the following piece of code:
   
   <div id='left-sidebar-wrapper'> <b:section class='sidebar' id='left-sidebar' preferred='yes'/> </div>
   
   Let me explain the elements of this code to help you understand what we've just done:
   
   
   
   • <div id='left-sidebar-wrapper'> This section tells the browser that the left-sidebar element exists here, and to look in the css for the appropriate styling for this element.
   
   
   • <b:section class='sidebar' id='left-sidebar' preferred='yes'> This tells the browser the class of the sidebar element and all other elements (widgets) which may be included in this section. The ID of this element must be "left-sidebar" in order to make it unique, otherwie this would cause problems when viewing. It is preferred so that it will feature in the layout, even if no widgets are placed within it.
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9. If you preview your template, you will notice that the right sidebar will be beneath the main section at the moment. This is because the outer-wrapper is still only wide enough to accomodate one sidebar. So now we need to expand the oputer wrapper to accomodate this new sidebar. Find this section in the HTML code:
   
   /* Outer-Wrapper ----------------------------------------------- */ #outer-wrapper { width: 660px; margin:0 auto; padding:10px; text-align:left; font: $bodyfont; }
   
   We need to increase the width of the wrapper by the width of the left-sidebar-wrapper, in this case 220px. So, change the value in red to 880px.
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11. You may also want to change the width of the header-wrapper to 880px so that it spans the new width of your blog:
    
    #header-wrapper { width:880px; margin:0 auto 10px; border:1px solid $bordercolor; }
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13. At this point, you should save your template. At present, your new sidebar will not be seen as there are no widgets contained within it, though it will still be present in the markup of the page. Once you have saved your template, go to Template>Page elements in your Blogger dashboard.
    
14. You can now add a page element (or two) to your new left sidebar.
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16. But we aren't quite finished yet! If you add anything to this left sidebar, you will probably notice that it jams right up to the main section. This is because there is no space defined between the left-sidebar and the main section. We need to create this space in the template's HTML. To do this, we will add a margin to the left hand side of the main posts section. Find the following code in your template's HTML and add the code defined in red:
    
    #main-wrapper { width: 410px; float: left; margin-left: 20px; word-wrap: break-word; /* fix for long text breaking sidebar float in IE */ overflow: hidden; /* fix for long non-text content breaking IE sidebar float */ }
    
    This defines a margin space of 20px between the left-sidebar and the main column. You should also ensure you adjust thw width of the outer-wrapper from 880px to 900px to ensure the width of your blog is enough to accomodate this margin too. Either that, or you could reduce the width of your main column/a sidebar by 20px to serve the same purpose.
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18. Everything complete now, so save your template and enjoy your new sidebar!

You can use this principles described to create a three column template from any Blogger template, though you may find that you'll need to adjust the width, margins and padding for your new sidebar in order for it to look the way you would like.

If you prefer to move your new left column sidebar to the right, you can configure the floating point of your new sidebar by set the CSS style sheet. Just change float to the right.
For reference, you can download the three column Minima here:

Download 3 column Minima template