Even after changing the button? Did you see it before and now its gone?
If you're talking about the game's help screen, You must be IN GAME for it to work. It will not work from the main menu. F1 does something different for some people on some OS, so I included an option to toggle the key needed to press to the letter "c" on your keyboard. In order to toggle this, you must go into the game setting and go into the "Advanced" tab (button near top) to go to the page where it is on.