simple you follow this steps. Sign in to your blogger dashboard>click the 'layout' button. Click on the 'Edit html' tab. add your mata after this one <b:include data='blog' name='all-head-content'/>
you can find more detail here http://growyourblog.blogspot.com/2008/03/how-to-add-meta-keyword-and-description.html"]
I wonder where is the code of meta description. Find on net and here is the result for any one do no know code: (like me) <meta content='DESCRIPTION' name='description'/> <meta content='KEYWORDS' name='keywords'/> <meta content='AUTHOR' name='author'/> Good luck to you. Once more thank you for your clearly instruction
There is a round a bout way of doing it, from memory it has something to do with changing the title tags in the HTML of blogger. I will post again soon after I have another look!
You can create all the meta tag codes by entering the information in some fields online at http://seotools.bloggertricks.com/free/online-meta-tags-generator-tool/