While installing your IPS Community Suite, you will be given the opportunity to choose your default application. However, we realize you may not know at that point in time, or indeed change your mind on what you want the default application for your suite to be.
In a nutshell, your default application is what your user sees when they visit your sites main URL. So for example, if you set this up as gallery, then the first thing that people will see on your site would be the gallery home page.
You set up a default application from your applications section within the admin CP. This can be found at System>Site Features>Applications, and will look similar to the following.
In the above image you will see one of the stars is selected on the right. This is what denotes the default application on your site. You can select any of the star icons so change the default application.
Each application is built up of modules. For most, you may only see one module under that application. For example, the forums application only contains a single forums module. In some application such as commerce and system, you will see more than one. For example, you may wish to set commerce as your default application and have the subscriptions module as the default module to be viewed when commerce is visited.
You will note you can set up the system application as the default application, but then what would that show? If you expand the system application, you will see that you can also set a default module. In the example below, I have set this to be the status updates page.