Learn how to add subdomains to your main domain (Example: blog.yourdomain.com or support.yourdomain.com).
Firstly you will need to log into you HostGator account. Once logged in, go to Hosting > Domains.
Select Subdomains and you will be directed to this page below.
Now all you do is add what you would like your subdomain to be in the first box, select the domain you want the subdomain to come from, leave Document Root blank and select Create.