Complex sentence: He wanted the memex to behave like the "intricate web of trails carried by the cells of the brain", but easily accessible as "a future device for individual use... a sort of mechanized private file and library" in the shape of a desk.
Split into simpler sentences: He wanted the memex to behave like the "intricate web of trails carried by the cells of the brain". It was also important that the memex could be easily accessible as "a future device for individual use... a sort of mechanized private file and library" in the shape of a desk.