Set Up A Custom Domain For Your Blogger

Captions

Add www. to your domain

To change your domain (example: mydomain.com) to www.mydomain.com, set up a naked redirect.​

1. Go to your domain provider’s website.
2. Open your DNS settings.
3. Enter your domain name in the format example.com.
4. Add four A-records which point to Google IPs.
   • 216.239.32.21
   • 216.239.34.21
   • 216.239.36.21
   • 216.239.38.21
5. Sign in to Blogger.
6. Select the blog you want to update.
7. On the left, click Settings  Basic.
8. Under "Publishing,", under "Blog Address," check Redirect [mydomain.com to www.mydomain.com].

Steps
Type the 4 dns which has given above this in your manage freenom setting and you are done.

doubts regarding this,watch my video or,

                                    visit: https://support.google.com/blogger/answer/1233387?hl=en&ref_topic=6321959