Install an application on your site :

A) click on Web Applications in the hosting group

Install or remove ASP.NET Web Applications on/from the domain.
 

Click Install New Web Application in the Tools group. A list of site applications available for installation will be displayed. To specify which application you wish to install, select a radio button corresponding to the application of your choice.

Click Install.

Specify the domain folder in which the application should be installed, database name for the application, and click Install.