They use your Military experience as a base line, for this position you have an exam, where you are asked over 100 questions to determine your ability to diagnose the Abrams Tank platform it is very intense. Now days you have to undergo an Field Service Representative academy that last about 4 or 6 weeks. The class is very intense and knowledgeable you will learn basic electronics, safety, electrical diagrams, hydraulics, Abrams turret, Abrams hull systems, Fire Control and track maintance.