How to slide over?

I agree with you completely there especially that you can no longer know now if an app supports Slide Over/Split View. The only option you have is just putting an app in a Dock an simply try and see if it works.

On iMore they described and put some GIF images of the new iOS11 kind of way for Slide Over and Split View. There is also the option to use Spotlight search from the Notification Center so it seems.

I'm still using iOS10.3.2 on all my iDevices because of various reasons.

 

You don't need the apps in the dock, you can use multi-touch to launch it instead.

1. Press home to get to the home screen
2. Touch the app you want in slide over and hold for a second until it slightly enlarges
3. Press the app you want in full screen (changing home screen pages by swiping if required) as normal to launch
4. Drop the app you touch and held originally into slide over at the left or right of the screen

 

Once you have initiated slide over you can swipe the app off the screen and then later swipe from the right to bring it back just like iOS 9 and 10.


As well as iniating multitasking from the dock, you can drag an app icon from the home screen and use another finger to open another app. Also you can drag app from home screen onto an app space in the app switcher wait for it to animate slide over and release.

Finally if you have a keyboard attached you can initiate spotlight search (Cmd + space bar) and drag an app from there.




Also you can move a slide over app from left to right side of screen by swiping (left or right) on the bar at the top of the app. You can also swipe from the sides of the slide over app to do the same thing and can do a big swipe to the right to swipe it off the screen and then later swipe from right edge of screen to bring it back just like iOS 9 and 10.

If you pull down on the bar it goes from slide over to split screen and vice versa. You can even switch split screen apps from one side of the screen to the other by grabbing and swiping left or right on the bar at the top.

And of course you can resize the split screen by swiping on the grey bar dividing the apps.

I hope that makes sense. Here is a screen recording: