This helpful guide will show you how to create a subdomain in cPanel.
First of all, you need to be logged into cPanel, not sure how? Please read our guide on how to login to cPanel.
Now logged into cPanel, scroll down until you see the header "Domains" then click "Subdomains"
Next, you will need to type your desired subdomain in the box labelled "Subdomain" then hit click the "Document Root" box, which will be auto filled for you.
All that is left to do is hit create.