Thanks to Cpanel, this task has been made easier than ever and can be achieved as follows:
1. Login to your control panel (http://www.yourdomain.tld/cpanel)
2. Select Subdomains
3. Enter the name of your new subdomain
4. Hit "Add"
Your new subdomain is now ready for use. To find it, login to your "main web directory" through your control panel by selecting "File Manager " or simply use your favorite FTP client. You'll see it listed as another directory. Upload your files to this directory to upload content for that subdomain. For example, if you created example.yourdomain.tld, then a directory called example is what you'll be looking for.
All subdomains are created with their own independent cgi-bin. This means your new subdomain operates independently of everything else, and is almost like having a whole new domain.