How to Organize Home Screen Icons in Folders?
citation from side http://www.gsmarena.com/samsung_galaxy_a3-review-1174p3.php : In the app drawer, icons are presented as a customizable or alphabetized grid. You can also view only the ones you've downloaded yourself or just hide the ones you don't need. You can also disable some of the pre-installed apps so they won't take up any RAM.

try change launcher (Nova):
How to create folder in app drawer of galaxy A3?