If you wish to install WordPress on your sub-domain, there will be changes on the Domain section as per the screenshot below:
- Login tocPanel via yourdomain.com/cpanel
- Locate Softaculous Apps Installer
- Locate WordPress follow by Install
- On the Choose Domain section, choose your desired sub-domain on the drop down menu
The In Directory section should be blank or else the WordPress shall be install at sub.yourdomain.com/wp