Applications Installer is a great Tool that allows to equip your web site with popular web applications.

To view the list of available web applications, click Application Installer menu item on your space page. Application Installer page will open.  

Note that almost all web applications require database, so make sure you have database option available in your hosting plan.

To install web application, just choose it from the list and click Install button. Install Web Application page will open.  

Enter web application settings and click Install button.