Before installing the prefab make sure you have these packages also installed in your unity project in order to correctly install the prefab.
Note: You need to be on VRChat Avatars SDK 3.5.2 or later as that is the SDK update which introduced the ‘Animator Play Audio’ State Behavior. The Boombox does not work w/out it.
VRCFury - v1.859.0 or later