Working with custom sounds for creatures.

Hello, readers! Has anyone added their own sounds to replace something from the standard set (not dialogues in cutscenes, but sounds like hero footsteps, the sound of a swordsman's attack, etc.)? I want to create my own hero and give him a unique firing sound. I have the sound, but how do I configure it for the game so that it doesn't play loudly across the entire map/arena? Is this configured in the editor, or do I need a separate program?