How to create a Subdomain in cPanel?
From A to Z: How to Create a Subdomain in cPanel
The complete guide to create a manual backup from cPanel
Step 1: Login to your cPanel
Step 2: Make sure your the default theme is Jupiter
Step 3: Click the Domains button in Domains section of cPanel
Step 4: Click Create a New Domains button in the right corner
Step 5: Type the subdomain name followed by domain name and click Submit button
Example in the image bellow. In the example I used the subdomain my