Open the first app
Swipe up slightly from the bottom to show the Dock
Touch and hold the second app in the Dock
Drag the second app to the left or right edge of the screen
Release it when the split view preview appears
Adjust the divider to change the screen size of each app
To remove split screen, drag the divider all the way to one side
If the Dock is not visible, swipe up from the bottom again
If Split View is unavailable, check that the app supports multitasking
If needed, enable multitasking in Settings > Home Screen & Multitasking > Multitasking