F2F is a simple program to compare 2 files. If they are different, it tells you the first different byte location from the head ('Forward' Comparison) or from the end ('Reverse' Comparison). Please see the status bar after pressing one of the comparison buttons.
You can easily select files to compare, by the 'Browse' buttons or drag & drops from folders. You can also open the files by 'File 1' and 'File 2' buttons. Please refer to the tooltip and the status bar help text, which appear when you move the mouse pointer onto the item (menu, button, window) you want to know.