I feel like I'm missing something obvious here?

So, I figured out the >!chessboard puzzle!<. That led me to >!the rook power, and the demand hidden in the wall that I should CASTLE!<. So, I spent A very long time to >!spawn the Rook room (conservatory) and King room (office) in the appropriate positions!< to have them >!castle, and then returned to the chessboard and put the pieces on and tried to castle them!< ... and not a goddamn thing happened. Have I just wasted my time entirely?