This is a really stupid problem. In the Apps section of my Samsung Galaxy J5 Prime (SM-G570M) I can't seem to edit and drag icons around the page to my own custom order. Whenever I click on an icon it immediately copies it to the home page and then provides options in a box which I barely have the time to press with my other finger. There is no option for 'Edit' in the top three dots at the top of the page. The only options I can see are: Sort, Clean up pages, Settings and Galaxy Essentials.