For Set up a custom domain so that your original Blogger address automatically forwards to your new domain. Here is complete step by step please follow
1. Sign in to Blogger.
2. In the left menu, click Settings > Basic > Publishing.
3. Under your current domain, click Set up a 3rd party URL for your blog.
4. Enter your URL, including the www.
5. Click Save.
6. An error will appear with two CNAMEs.
Ex: Name, label or Host Field
Destination, Target or Points to field
Enter the CNAMEs provided in the error message and click Save.
It may be done within an hour or it may take 24 hours to complete the process. if you see an error message after time interval try this same process again. It not done properly then contact your domain register for further help.
Host Name/Alias: www
This is the part of your website’s address that you designated. For example, if www.mydomain.com is your address, enter www.
Value/Destination: <YOUR DOMAIN>.ghs.googlehosted.com
For example, if you chose www.mydomain.com as the address, enter www.mydomain.com.ghs.googlehosted.com.
Optional: You can also enter A-records, which link your naked domain (example.com) to an actual site (www.example.com).
Enter your domain name in the format example.com, and list the IP addresses shown below in the “A” section. You’ll need to add four separate A-records which point to four different Google IPs.