Complex sentence: Soon after Peter's surrender, Gomez announced that the American Marines were no longer needed so they began to withdraw, first to the naval base at Guantanamo, and then to stations in the United States.
Split into simpler sentences: Soon after Peter's surrender, Gomez announced that the American Marines were no longer needed. They began to withdraw, first to the naval base at Guantanamo, and then to stations in the United States.