Hi
Here is an overview of the process

Use cpanel to create the subdomain
Download the latest version of wordpress to your local drive
Upload to subdomain folder on your host
Extract the files, and move them into the subdomain folder
Use cpanel SQL Wizard to create a new data base
Make a note of the username, db name and db password
Copy wp-config-sample.php to wp-config.php in the subdomain folder
Edit wp-config.php to add the username, db name and db password
Open the URL “your-subdomain.your-domain.com/wp-admin/install.php”
Fill out the fields on the form and press “install wordpress”
After creating the a subdomain I use WP clone to create and install a backup of my live site into the new subdomain. The clone site allows me to verify updates before deploying them my public site.

Hopefully the OP has resolved this issue, but maybe this will be of use to others.