Complex sentence: Brannan's dreams of colonization and success were underway and after leaving Hawaii, the "Brookyln" changed routes, landing on July 31,1846, at the Mexican port town of Yerba Buena.
Split into simpler sentences: Brannan's dreams of colonization and success were underway and after leaving Hawaii, the "Brookyln" changed routes. The "Brooklyn" landed on July 31,1846, at the Mexican port town of Yerba Buena.