you first need a character.
There is a thread titled Canon Characters, where there are characters there for you to take. if they arestriked then someone has them.
you can also make up your own character.

Once you choose your character, you then make a profile, in the profiles thread, using the profile I have provided to you.
Once I see you have posted, i will then sort you.

If you would like to be a prefect or play quiditch, post so in the threaded titled:
quidditch teams and Prefects.
Then, you are done!
Post away, my friends!