How do I jump onto the ledge with the pressure plate in Alice (Ch 1 - Smelling & Regurgitating)?

Question

I'm new to games, and spatially challenged :-) Loving Alice so far! I'm stuck in Ch 1 - Smelling and Regurgitating - where the Cheshire Cat tells you to use the steam to make your way higher. The logical path to jump onto the ledge with the pressure plate is from the thin ledge under it - but I've tried with no success so many times - it's just too high. The walkthrough I found seems to follow this path. Am I doing something wrong? Thanks :-D