After adding a domain into your DNS Made Easy account, you can add the necessary subdomains to it.
Let's say that our domain subdomain.testserver12.com points to 184.108.40.206. In that case, we would create an A record within the domain testserver12.com of name "user" and the IP value 220.127.116.11 just like in the picture below.
Our domain user.testserver12.com points to alldomains.com. In that case, we would create a CNAME record of name "user" and "alias to" value "alldomains.com".
In case you have other remaining records types that need to be added within your domain, all you have to keep in mind is that, if you are adding a record for a subdomain, then you would just add the subdomain into the "name" field, and consequently the value.