To create Split View on the iPad…
Using iOS11 you can use Multitasking to work with two apps at the same time. You might want to answer emails while watching a video or scroll through your photos to select one or two to add to an email.
If you want to enter Split View this is easier if the second app you want to work with is in your Dock.
Open the first app. I have opened App Store.
Swipe up from the bottom of the screen to display the Dock.
On the Dock — touch and hold the second app that you want to open.
Drag it to the right or left edge of the screen — the first app will move aside.
Drop the second app (in my case it is Photos).
To adjust Split View
To give the apps equal space on the screen, drag the app divider to the centre of the screen.
To turn a Split View into a Slide Over, swipe down from the top of the app you want as a Slide Over.
To close Split View, drag the app divider over the app that you want to close.
To replace an App in Split View iOS
Follow the link here.