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1. Go to Blogger Settings > Basic > Click on Add a custom Domain.
2 It will ask your custom domain. Now enter your custom domain like www.example.com. It will give two CNAME record's. Now you have to enter these CNAME values into your DNS record's.
3. Open your Domain Account Go to Manage website > DNS Manager > Add both CNAME value given by blogger.com. Save all the settings. It might to take up 24 Hour.
For More information You can check this Google Instructions :- How to use Custom Domain .
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