Galaxy S4 can run many different types of applications, ranging from media to Internet applications.
Opening an application on Galaxy S4
On the Home screen or the Applications screen, select an application icon to open it.
Opening from recently-used applications
Press and hold the Home button to open the list of recently-used applications. Select an application icon to open.
Closing an application on Galaxy S4
Close applications not in use to save battery power and maintain device performance.
Press and hold the Home button, tap , and then tap End next to an application to close it. To close all running applications, tap End all. Alternatively, press and hold the Home button, and then tap .