With respect to hierarchy, domains are read from right to left.
Top level domain (TLD) examples are .com, .net, .org, etc.
A second level domain would be your domain within a top level domain.
Third level domains are the next level within a second level domain.
1st level domain: .com
2nd level domain: yourdomain.com
3rd level domain: john.yourdomain.com or www.yourdomain.com
Sub-domains are really nothing more than re-directs to a folder within your domain. In this example: www.yourdomain.com the ‘www’ part is a re-direct to your document root folder in your domain which is a folder called public_html.
Likewise, johnw.yourdomain.com could be a re-direct to a hard to remember folder in yourdomain.com that looks like this: yourdomain.com/classes/history101/students/johnw.
Login to your cPanel account and scroll down to the Domain category. Click on the Subdomains icon.
Then enter the name of the new sub-domain you’d like to create.
Click your mouse in the Document Root field and it will automatically populate it using the new sub-domain you just entered. Behinds the scenes, cPanel will create a new folder within your domain with this name and will point the sub-domain to that folder.
Click the Create button to create the sub-domain.
cPanel has now created a folder for your sub-domain in your public_html directory. This is where you will upload your files for the sub-domain.
A sub-domain called ‘tutorials’ would look like this:
It can also be accessed like this:
Click the Go Back link and you’ll see the new sub-domain listed on the page. You can return to this page at any time to create new sub-domains or delete existing ones.
Although it’s not necessary for the sub-domain to work, you can also grant virtual FTP access to the new sub-domain from the FTP Manager in cPanel.