Setting Big Rock Custom domain as third party Custom url in Blogger
Step 1 : In your blogger Account. Go to settings -> basic as shown in below screenshot.
Step 2 : click on set up a third party url.
Step 3 : Enter your domain and click on save, a message will be shown (We have not able to verify your authority to this domain).
Step 4 : Open your Big Rock Account and click on your website link as shown in the snapshot.
Step 5 : Scroll down to DNS Management and click on Manage DNS.
Step 6 : Insert these 4 A Records.
i. 216.239.32.21
ii. 216.239.34.21
iii. 216.239.36.21
iv. 216.239.38.21
Step 7 : Click on CNAME Record and insert the record as shown in the below snapshot.
Step 8 : Insert second record and click save.
Step 9 : All done just go back to your blogger and click save.