Perhaps this helps:
Swipe from the top of the display twice (or swipe with two fingertips once) to find a pencil 
icon on the right. Tap on the pencil and go into the button options in the lower half. By holding and moving an icon you can drag it into your selection in the upper half. Once you have done that, you might need to go back with the left arrow in the top left (I’m not sure if this is needed to confirm the re-arranging).