Samsung Galaxy S6 Edge: How to Open Multiple Apps at Once in Pop-up View in Android 5.1.1 Lollipop

In Samsung Galaxy S6 Edge, the multi window feature gets an improvement because now you can not only open two apps at once in the split screen view, but also open multiple apps at once in the pop-up view. It's a cool and easier way to multitask in your phone because you can easily do several tasks(e,g: you can easily share a nice post you find while browsing to your friend via message and save it