Original: Waugh writes that Charles had been "in search of love in those days" when he first met Sebastian, finding "that low door in the wall... which opened on an enclosed and enchanted garden", a metaphor that informs the work on a number of levels.
Simplified: This act had also influenced Charles, who had been "in search of love in those days" when he first met Sebastian, "that low door in the wall...which opened on an enclosed and enchanted garden,", an important metaphor in the book.