How do you get to world 7 on super Mario bro Wii?

first thing you do is finish world 1 then you move onto world 2. once you have completed world 3 then you try finish world 4. then when you on world 4 you compleat all the levles on world 4 and then you move to world 5. then you compleat world 5 and then move to world 6 and then when you finish world 6 you are then on world 7 and that is how it is done