I need to know how fuel cms make routing I enter to config/routes I found that the default controller is fuel/page_router how does th fuel/page_router located and how does it work ?
That controller is located in the fuel/modules/fuel/controllers/ folder. FUEL will look for controllers in the fuel/modules/{module}/controllers folder. For example, you can create an advanced module named my_module and have a corresponding controller at fuel/modules/my_module/controllers/my_module.php and that can be viewed at /my_module
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More on advanced modules here:
http://docs.getfuelcms.com/modules/advanced