Log in to your account manager.
Select the Installatron icon located under the Web Site section of your accont. A list of your hosting plans and the domain names associated with them will be displayed. Select the hosting plan that has the domain you wish to install software to and you will be taken to the Installatron application browser.
Select the software you wish to install and on the following page click "install this application" in the upper right.
The next page provides a number of options to customize your installation such as automatic updating and backups.
Once the options are set to your liking click "Install" in the bottom right to being the software installation.
Once the installation is complete you will receive an email indicating so at which point you can then log into your new software installation.