Steps to set up Google AdSense on your blog:

• Go to the Blogger website. Use the left-hand link or type 'www.blogger.com' into your browser. In the upper-right corner of the window, click SIGN IN, then enter or click your Google ID and password. Then select Sign in.
• Activate the button. It's next to the blog title in the upper-left corner of the window, underneath the term 'Blogger.'
• Choose a blog. Click the title of the blog to which you'd want to add Adsense advertising in the drop-down menu. It'll either be in the 'Recent blogs' or 'All blogs' section. If you don't already have an Adsense account, you'll need to create one and wait for approval before you can use AdSense advertising on your site.
• Select Earnings from the drop-down menu. It's next to a '$' on the left side of the window.
• Before you can link your AdSense account to your blog, it must be qualified for AdSense.
• Sign up for Adsense by clicking the Sign Up for Adsense button. It's a blue button in the window's right pane.
• Sign in by clicking the Sign In button. To link AdSense to your blog, follow the on-screen prompts to sign in with the Google account associated with your AdSense account
• Return to Blogger.com if you are not instantly returned to your Blogger dashboard. Select Earnings from the drop-down menu. It's next to a '$' on the left side of the window.
• Select 'Yes' from the drop-down menu. It's near the top of the window, close to 'Show advertisements on blog.' It's supposed to be blue.
• For your blog, choose an ad configuration. To do so, select one of the following ad setting options and click the radio button next to it:
• 'Place advertisements underneath my post and on the sidebar'

Read More : What should I have done to approve AdSense in my blog?