Posted by ArchangelRenzoku
The feature you're looking for is called pen-window, and already exists on your note 4. Simply open Amazon prime, then take out the S-pen and hit the button while hovering over the screen to activate the action menu (if it didn't already appear) then select pen-window and draw the size of the area you would like the new app to encompass. Choose from the available apps. It's how I'm able to put YouTube in the background and still text and browse at the same time using multi-window as well.