Toyota Repair: cam timing, cam gears, toyota corolla

Question
i have a toyota corolla and i need to insall a exaust cam due to came loose  how do you set the cam timing the 2 dots on the front or back of cam gears or am i realy off im using a chilton manual. its a 1600 or a 1.6 liter

Answer
I need more information, what year is it and what is the engine designation, ie: 4AF-E, 7AF-E, 4AG-E etc., you can find this information on the underhood label, also if you can send me an email address I may be able to send an illustration back to you.