Stuck on Lego Harry Potter - Year 3 giant guard

I normally wouldn't do this, but I've been stuck for days and there are no answers to this online at all. I'm n year 3 in lego harry potter, before I have yet to meet Buckbeak. There is a giant guard guarding the door I am meant to go in and I can't for the life of me find out how I'm meant to pass him. For a kids game this is bloody difficult!