Complex sentence: Together, the American forces in Cuba totaled 2,789 officers and men and were organized into the 1st Provisional Marine Brigade, about half of which were sent to occupy various towns and cities in eastern Cuba.
Split into simpler sentences: Together, the American forces in Cuba totaled 2,789 officers and men and were organized into the 1st Provisional Marine Brigade. About half of them were sent to occupy towns and cities in eastern Cuba.