Complex sentence: Airborne soldiers were expected to fight against superior numbers of the enemy armed with heavy weapons including artillery and tanks, so training was designed to encourage a spirit of self-discipline, self-reliance and aggressiveness.
Split into simpler sentences: Airborne soldiers were expected to fight against superior numbers of the enemy, armed with heavy weapons, including artillery and tanks. So training was designed to encourage a spirit of self-discipline, self-reliance and aggressiveness.