Once you have a domain (if not purchase it), after purchasing and having it active. Here I am using Bigrock.
Follow these simple steps:
Step i: Login to the cPanel of your domain.
Step ii. Click on DNS management => Manage DNS.
Step iii. A admin area of the domain pop ups in a new tab with some records that can be edited (like A, CNAME, AAAA, NS, TXT, etc)
Step iv. Click on CNAME records => Add CNAME Record.
Step v. Type the host name (e.g. contact.domainname.com, editor.domainname.com)
Step vi. Check on Domain Name under value and type in there :
Step vii. Let the TTL remain 38400(seconds) and click Add record.
|Click on the image to enlarge|
Step viii: Go to blogger => Create New Blog => Add Title => Add Address => choose dynamic template.
Step ix. Go to the settings of the newly created blog, under Publishing in Basic settings, Add the newly created subdomain url as custom domain name. Click Save settings. Wait for the domain to be active for two days.
Enjoy creating subdomains for each page you do. Thank you and hope you liked it.
Here is an Example