On the Installatron page you will see a list of all hosting accounts and the domains associated with each one.
Select the hosting account that has the domain you wish to install Wordpress to and you will be taken into the Installatron app.
While in Installatron click the Applications Browser tab in the upper right to view all available applications.
Scroll down to the Apps for Content Management section and click on the Wordpress icon and then the "Install this application" button in the upper right to proceed to the installation page.
On the Install page under the Location section choose the domain you wish to install Wordpress to.
All other options can be left as they are but under the Settings section you may wish to change the Administrator username and password as they are randomly generated.
Once all settings are to your liking scroll down the very bottom and click the Install button in the lower right.
Installations typically take 5-10 minutes to complete.