Where are the stairs in Lego Harry Potter 1-4?

Answer 1

These were actually my last two characters to find. It was soooo frustrating and I felt so stupid when I found it myself. Remember the first time you go to Hagrid's? Well, you explored the grounds? I remembered that there was another set of steps on the left, right after you exit the bridge(going to Hagrid's). You go left, go all the way down, and use the pink plate with Hermione and voila! But maybe you've found it already....

Answer 2

When you are in the room that you can go straight into the Great Hall, go right onto the stairs. (This is the same in LEGO Harry Potter Years 5-7.)