Complex sentence: He fought off the shores of Guam and arrived at Guadalcanal with the Second Fleet; his main battles were Vella Lavella, Saipan, Tinian, and Bougainville.
Split into simpler sentences: He fought off the shore of Guam, arriving at Guadalcanal with the Second Fleet. His main battles were Vella Lavella, Saipan, Tinian, and Bougainville.