I was jsut giving you some hints.
Now is up to you, to define it the right places.
Try look at the source and use common sense to figure it out.
You wouldn't put a check for skills in level up right?
Is just like playing with the different objects you had when u were a baby.
The triangel, The Square and The Circle.
U wouldn't put The Triangel in the The Square, would you?
Best way to learn is from ur mistakes

So, try out.