If you want install WordPress on your sub domain then firstly you need to create a Sub-domain.
If you do not know how to add a Sub-domain in your hosting plan then your can read this for help:
How to add a Domain as Sub domain in cPanel
After creating sub domain you need to follow the following steps for installing WordPress on your Sub domain
Step1: login to your CPanel
Step2: Under Softaculous App Installer section . Click on "Wordpress" icon in the Softaculous app
Step3: Click on button in the navigation bar.
Step4: Then scroll down to "Software Setup" and enter the following details:
Choose Protocol: Select "http://" from the drop down. This will install WordPress on "yoursubdomain.com". If you have SSL installed on your domain then select "https://" option.
Choose your Domain make sure select your sub domain: Choose your sub domain on which you want to install wordpress.
In Directory: Delete by default written "wp" directory to install WordPress on your root directory. Not deleting it will install WordPress on "yoursubdomain.com/wp". So you must leave this field blank.
Step5: Enter the following details under site setting section:
Site name: Enter the name of your blog/website. For example: "XYZ Publications".
Site Description: Enter basis description of your Website. Example: "My Own Blog".
Enable Multisite (WPMU): You Don't need to check the checkbox. Leave it as it is. If you are Checking this option will enable WordPress Multi on your domain (Not Recommended).
Enter the following details under "Admin Account" section:
Admin Username: Set your user name to login to your WordPress. This will be your username for your WordPress admin panel.
Admin Password: Set your password for WordPress admin.
Note: We recommend you to choose password generator to set password. Because it generate safe passwords which cannot be guessed by anyone.
Admin Email: Enter your email that you want to use with your admin.
You can use your gmail/yahoo or any other email as your admin email or you can also create emails from cPanel on your domain and use your Custom Domain email like email@example.com as your admin email.
create emails from cPanel on your domain and use your Custom Domain email like firstname.lastname@example.org as your admin email.
Step6: Review the Following options:
Select Language: By default English is already selected. So you don't need to change the language.
Limit Login Attempts (Loginizer): Please don't check this. It is not recommended, so leave this field as it is.
Advanced Options: Please do not make any changes in this section.
Select Theme: You can leave it for now. It is optional if not selected the default theme will be installed and you can make changes later on from your WordPress library.
Email Installation details: Enter your Email in this field at which you want to receive your WordPress login details after installation.
Step7: Click on and wait for the installation process to get complete.
After few minutes you will see a message Congratulation, Your software was installed successfully. You will also receive a confirmation email on your email that you have entered during installation.