1. login to your cPanel by going to: http://www.yourdomainname.com/cpanel (yourdomainname.com should be replaced with the domain name you're hosting with MacHighway)
2. In cPanel, click on Subdomains under the Domains section
3. In the Subdomains module you will see the following fields:
Subdomain: Put in the name of the subdomain you want to add (i.e. clients, if you want to setup clients.yourdomainname.com)
Document Root: cPanel will automatically populate this field for you. Unless you have a specific folder that you know you want your domain name to use as it's root directory, leave this as is.
4. Click the Create button to create the subdomain
Use your FTP username and password and the document root created for your Subdomain (ex. public_html/clients) (see fig. 1)
If you're unsure of the correct Document Root for your Subdomain, you can login to your cPanel, click on the Subdomain module and scroll down until you see your active Subdomain. The Document Root will be listed just to the right of the Subdomain name. (see fig. 2)