Everything is written in the manual. Add the animation with the code name name = rangeattack to AnimSet in HeroCharacterArena, and in BasicSkelAnim, choose one of the existing animations (screenshot in the manual). The Archdevil also doesn't have a melee or ranged attack, so the manual describes how to add it.
P.s. Textures are responsible for displaying the model, not for the absence of animations.
It helped, thank you very much!