Tap the Home Button > the Recent Apps Button > Dual window to split the screen.
While viewing an app, you can tap the Recent Apps Button > Dual window to automatically set that app in the top window, then select the second app.
While viewing the Recent Apps screen, tap the Dual window icon on an open tab's titlebar to automatically set that tab in the top window, then tap Dual window and select the second app.
Tap the app icon you want to use. The first app you tap opens in a window at the top of the screen. The second app opens in the bottom window.
Tap a window to select and use it.
A blue box appears around the selected window with a blue semicircle handle between the windows.
Drag the blue handle to change the window sizes (one larger and one smaller).
Tap the blue handle to access the Dual window options.
Tap the Swap icon to switch (flip) the app positions.
Tap the View app list icon to redisplay the apps list so you can change the app for the selected window.
Tap the Open full screen icon to open the selected app in full screen. Drag the blue handle (or tap the Close full screen icon ) to return to Dual window.
Tap the Close icon to close the selected window.