That's a really foggy question
You perhaps mean that you don't see any text after typing "/etc/X11/xorg.conf"? If this is correct, that's probably because the file does not exist yet or because the file is empty... .
Anyway, to save your changes press "Control+X" (this exits and if you did any changes it will ask you if you want to save them) or "Control+O" (this immediately saves all your changes without asking you for confirmation).