Poptropica Pictures How Do You Get Into Mordred's Castle On Astro Knights Island On Poptropica?

How do you get into Mordred's castle on Astro Knights Island on Poptropica? - poptropica pictures

I know you have to move the fields to get the picture of Mordred, but it is a way to do this? I'm supposed to start at a certain tile? Please help! Thank you!