user profile

i am a complete beginner in codeigniter and try to learn the basics of this framework.i made a login form and signup form.now i was thinking of making a user profile.i want the logged in username that gets showed on the page automatically for the logged  in user"$username".i have made a new controller ,model and view for profile.i have loaded all the models in my controller,can someone help me ,how can i get data[] that will have the entire information of the logged in user and i can use it in my profile calss and display it on the profile view.
i am a complete beginner.thanks