Here is my original tutorial on domain mapping with Go Daddy. Although if you need help with domain mapping and another registrant, just let me know.

https://www.blogsbyheather.com/2009/02/domain-mapping-with-blogger-and-go-daddy.html

In short, basically you are modifying the CNAME record (www).

Name: www (for example)

Points To: ghs.google.com

Then once you complete the settings in Blogger (as explained in the above linked tutorial), and save changes, you can click on the check mark about forwarding http://handstampedbyheather.com to http://www.handstampedbyheather.com (for example).

So, now if you go to http://www.handstampedbyheahter.com or http://handstampedbyheather.com they both work and go to my Blogger account.

Happy Blogging!