Method1:
a) Touch the 
icon at the bottom of the screen, your recently used applications will be displayed.
b) If the current application supports split screen, there will be a split screen operation prompt at the top of the screen: “Swipe to corner to trigger float window/split screen”. Tap the split screen icon 
in the upper left corner or move the app to the upper left corner to split the screen.
Method2:
Go to “Settings” -> “Button & gestures” -> “Gestures” -> “Split-screen gesture”, then in the home screen or applications supporting split screen, swipe up with 3 fingers on the screen to activate split mode when the application supports split screen.
Note: This Q&A question only applies to devices with split screen function.
Available settings and menus may vary depending on device model and software version.
