#1 Log into your Blogger account with your username and password. Once you are in your blog's dashboard you'll see the word manage on the right, followed by three tabs: Post, Settings and Layout. Click the Layout tab.
#2 Look under the heading choices on the Layout tab. You'll see four choices listed: Page Elements, Fonts and Colors, Edit HTML and Pick New Template. Click the Edit HTML tab.
#3 Backup your template if you haven't already. This is always a wise idea and will let you easily repair any accidental mistakes that you may make when you edit the HTML of your blog. Once you have made a back up of your template save it on your computer.
#4 Hold down the CTRl button and the F key on your computer simultaneously. Make sure that you have placed your cursor in the HTML box first. This brings up a search or find window. Depending upon your Internet browser, it will either be located at the bottom or top of your computer screen.
#5 Copy and paste the following code into the search or find box.
#7 Fill in your information where it says 'DESCRIPTION HERE', KEYWORDS HERE', and 'AUTHOR NAME HERE'. Write a nice description that describes the purpose of your blog. Type in a list of keywords that describes the content of your blog and separate each term with a comma and then enter your name where it says "Author Name Here."
#8 Click preview and view your blog. As long as everything looks correct and there are no errors, click save.
Source: http://www.ehow.com/how_4432068_add-meta-tags-blogger-blog.html
