After you successfully create a subdomain on Cpanel and gave it up to 48hours to propagate.
Your domain is now ready for use.
Go to Files section on your Cpanel account.
Login to your Cpanel account and navigate to Files section. Select ‘File Manager’.
Open public_html folder
After you select ‘File Manager’ this will open a list of files and folders on your account.
Look for ‘public_html’ folder.
This is the folder that contains files and folders that can be accessed by the public such as the website.
Locate your subdomain folder.
In the ‘public_html’ folder look for the folder with your subdomain name.
This is the folder that will host your files to be accessed by the public.
Open the folder and upload your website files.