Refer the below steps to map your domain to your blog.
1.To Edit Your CNAME Record >Log in to your Client Login.
>Below the domain you can see the option Managed DNS.
>In the CNAME section, click the www record.
>In the Points To field, type ghs.google.com.
>Click Save and then click OK.
2.To Forward Your Domain Name >Go to support.google.com. https://support.google.com/blogger/answer/1734119
>Click Host my blog on a URL that I already own.
>Follow the listed instructions.
3.To Configure Your Blogger Account >Log in to your Blogger account.
>From the Settings tab, select Basic.
>From Publishing, click Add custom domain.
>Click Switch to Advanced Settings, and then enter your domain name. For example,enter www.demo.com.
>To specify another location in which to look for files, in the Use a missing files host? section, select Yes and enter the path. If not, select No.
Note : Any DNS changes you have made it take up to 48 hours to reflect globally.