How to move images and video to SD Card?
Yes, your advice flattens the directory structure.  

Therefore the only thing you can do is:


Go to My Files -> My Device.
Navigate to the files/folders you want to move
Select the files and folders you want to move
Hit More -> Move
Select the destination
Hit Done
Repeat steps 2 - 6 until you are done.


Files from the Camera app are located at DCIM/Camera/

For changing the default location of photos and videos, go to the Camera app's settings and change the default location.