FAT Sorter is a "simple" program to sort files on a FAT file system. The target scenario for it is to sort the files and folders on a USB flash drive alphabetically, so they are loaded properly on devices that read them.
The FAT file system doesn't support sorting directory entries. However, this is the only file system for USB flash drives that is widely supported. Unless the hardware or software accessing the device (like your computer) resorts them for display, the files will show in the order they were added to the directory.