To enable subdomain redirection, go to cPanel > Subdomains > Manage Redirection. Enter the destination and click Save. To disable, follow the same steps and select Disable Redirection.

To upload web files to a subdomain via FTP, access 'public_html/subdomain_name'. Alternatively, in cPanel's File Manager, navigate to ''public_html'' and the subdomain folder for file upload. Check subdomains created with addon domains in the specified root directory.

To create a subdomain in cPanel, navigate to ''Subdomains'' under 'Domain', enter the desired subdomain name, and cPanel will auto-generate a document root path. This path acts as a storage location for subdomain files. Click ''Create'' to finish. Remember, avoid using reserved names like cPanel and ftp.