How to setup your codeigniter projects

How do you guys arrange/structure your projects?

How do you guys structure your controllers? 

how do you separate your functions into specific controllers?

For example: login,logout,register functions should go inside accounts controller.

Let's say i want to make an online shopping web app using codeigniter.

Therefore i will have browse_items function and create_item.

The former doesnt need a logged in account but the latter needs an authenticated account.

Do i then make 2 versions of item controller and put them in separate subfolder inside my controller folder named private/public?