To unlock this achievement, you must equip the compound bow on your character when preparing for a wave.
To find the compound bow, you must travel to Whistler's Grove and search buildings there until you unlock it.
Note: You do not have to play a wave with the bow, equipping it on your character is enough. You can unequip it afterward and use your preferred weapon, if you like.
The achievement should pop the first time you equip the bow.