1.First go to Google AJAX Search API Wizards

2.Now Customize your blog bar

3.Enter your blog URL.

4.Click on generate code.

5.Now copy generated code.

6.Login to your blogger dashboard--> layout- ->Page Elements

7.Click on 'Add a Gadget' on the sidebar.

8.Select 'HTML/Javascript' and add your blog bar code and click save.

Now you are done.