Login to your cPanel Account,
Click Domains under the Domains section.
Now, Click the Create A New Domain button.
Enter the subdomain name to add in the "Domain" text box.
Deselect the "Share document root (/home/username/public_html) with “domain.tld”." option.
Enter the directory where you want the files for this subdomain to exist.
Click the "Submit" button.
Your sub-domain has been created successfully. You can upload your web content using FTP