Overview
All sound effects are played via the Audio Source component attached to the character:
Audio Source.
Animation Events
Many sounds, like reloads, aiming, walking, or fire mode switching are played via animation events. Events are added directly to the Animation Clip and then are automatically triggered in runtime. There are 2 types of animation events.PlayPlayerSound

Player sound event.

FPS Player Settings.
PlayWeaponSound
This event is added to reloading animations. Sounds are selected from:
FPS Weapon Settings.