ios play order

[mgj3030]

Ok
I must have missed something in the faq. It states you can drag and drop files within a folder. I am trying to set the order of play. Let us call the files f1,f2,f3,f4 ...
I used wifi to move them to the iphone and to my surprise the order was changed. Say f3, f5,f2,f1 and so forth. In other words the files now appear out of alphabetic order and plays as the order is shown. I can not drag and drop to correct position. The file highlights but does not move. What do I need to do to get the correct play order? Thanks