The door going inside has an eagle-head knocker that gives you a riddle. Answer it correctly and you gain access. Answer incorrectly, and you have to wait for another student to get it right. The answer to this riddle is 'The word "wholesome".' After that, you use the up arrow to your dormitory and the down arrow to the common room.
Rowena Ravenclaw, the founder J.K. Rowling, the writer _____________________________________________ and Ravenclaws only!