Age of Empires: Castle Siege

to unlock raiders you will need to upgrade your barracks to level 2, but that costs 1300 food. you will need to upgrade your silo to level 3 to be able to hold enough food. that upgrade costs 900 lumber. so you will need to upgrade your lumberyard to level 2 to hold enough lumber. the fastest way to earn enough food and lumber is to win multiplayer battles. train troops, i chose all 6 infantry since they are good at fighting towers, and that seemed to be the only defense i ran across at this point in the game. then go to the swords at the bottom left and choose "find opponents". as soon as the battle ends, train your troops again, build or upgrade what you can, and attack again when the troops are ready. also each multiplayer win will count towards another achievement: