Short-Ranged Cavalry: Both Cavalry sub-types attack enemy ranged Troops. A great way to attack is to use cavalry and Swordsman only. This way the high dps Crossbowman will die before they can kill your Swordsman. Swordsman deal small damage themselves, so its not a threat. Same goes with ranged Cavalry. Short-ranged Cavalry have a chance to dodge attacks, making them a second meatshield after Swordsman.
Range Cavalry: These sub-types attack an enemies back line. They deal extra damage in recourse fights. This means, if you are farming, use Range Cavalry. Because Spearman deal extra damage to Cavalry, the best gathering composition is 20% Swordsman 30% Spearman 30% Ranged Cavalry and 20% Assault Cart.