In short: To install WordPress manually: download it from wordpress.org, create a MySQL database and user in cPanel, upload the WordPress files to public_html (or a subfolder), then open yourdomain.com/wp-admin/setup-config.php, enter the database details, and complete the installation.
WordPress is the most popular website platform in the world, loved for its simple interface and huge choice of themes and plugins.
Step 1: Download WordPress
Download the latest version from wordpress.org (or the Arabic edition from ar.wordpress.org). Extract the .zip file; you will get a wordpress folder containing the files.
In cPanel, create a new MySQL database and a database user, and give the user all privileges on the database (see how to create a database and assign a user). Save the database name, username and password; you will need them during installation.
Step 4: Upload the files
Decide where to install WordPress: in the main folder (example.com) or a subfolder (example.com/blog). For the main site, upload to public_html; for a subfolder, upload to that folder. Upload with FTP or cPanel File Manager.
Note: upload the files inside the wordpress folder, not the folder itself.
Step 5: Run the installer
Open the installer in your browser: https://example.com/wp-admin/setup-config.php, or https://example.com/blog/wp-admin/setup-config.php for a subfolder (replace example.com with your domain).
Click Let's go!, then enter the database name, username and password you created, and click Submit.
On the success page click Run the installation.
Fill in your site title, admin username, password and email, then click Install WordPress.
Log in at example.com/wp-admin with the details you entered.
This is what the WordPress dashboard looks like after installation: