The draw is fairly easy but the author mentions a win. Any ideas?
Once you're on D7 the pawn can be captured or kept. If black moves to capture the pawn with a bishop, you move the king into pawn's old spot. You capture the black rook with the other pawn for the win.
If there are no more bishops on the diagonal, or if they move their king to the B column, then you get a Queen and finish them off.
Am I missing something (I'm a very bad player)?
If you capture the black rook, black will capture your pawn with the queen (and proceed to mate you now that their queen can move).
The mistake black makes is trying to get its king out of the morass as soon as the pawn moves, instead of just capturing the pawn with its bishops.