Complex sentence: Camp Santiago is the primary training area for the U.S. Army, Army National Guard, U.S. Army Reserve and the Air National Guard in Puerto Rico for Annual Field Training Exercises (FTX) each summer and for monthly drills throughout the year.
Split into simpler sentences: Camp Santiago is the primary training area for the U.S. Army, Army National Guard, U.S. Army Reserve and the Air National Guard in Puerto Rico. The camp is used for Annual Field Training Exercises (FTX) each summer and for monthly drills throughout the year.