There are two ways that you can use to install WordPress, one is that you install it manually through their website or you can do it through the application.
This is how you install it via the application:
First you need to login to your control panel (cpanel)
When you have logged in you scroll down until you find Web Applications, press view more and you will see all of our applications.
Scroll down until you find WordPress among the applications and press it.
Now you just click install this application and you will get a mail when it is done.
This is how you install it manually:
Go to this url: wordpress.org/download and download the files.
Then you need to create a database and a user for the database, then you connect these two together (you do this at the bottom of the same page you create databases)
Then you upload your files and put these under public_html if that is ”the main domain” if not you will find a folder with your domains name on it.
Write your database data in the config file.
Then you go to: yourdomain/wp_admin and complete your installation.