The Launch Pad is primarily a screen which allows navigation to all the homepages and applications you have access to on the site. It is accessed via the Apps icon at the top left of the screen. Click on the application to open it. The Apps are grouped together into "Categories" which are defined by the App Builder. The description which appears when the mouse moves over the App is the description of the App defined by the App Builder.
The My Apps section shows the Apps you are able to see, they show in order of category. Other Apps are available by clicking on the "View App Apps" option below the list of Apps
Apps are displayed alphabetically grouped by category. You can customise which categories of apps you will see by selecting them from the springboard filter area at the top right of the pane.
Hovering over an app icon will display some description text explaining what the purpose of the app is.
If your site has a number of applications then you can take advantage of the search functionality. This will filter down the springboard to show the apps where the search text is contained in the App Title or Category.