Hi,
If you want to connect your .com domain with blogger you have to follow below steps
You have to update following default nameservers
1. Go to Domains > click on manage nameservers and update following nameservers
1188.dns1.managedns.org
1188.dns2.managedns.org
1188.dns3.managedns.org
1188.dns4.managedns.org
2. Now you have to create DNS records for blogger
3. Go to domain DNS management and update your blogger DNS records
