Adding onto this, if you don’t want to have the full-body animate, and you just want the idle animation to have the weapon in the right place (or you want the knife to work with an animation pack you’ve already made and don’t want to remake it), simply create an animation, with the only keyframe being the handle. Adjust the keyframe how you’d like, and follow the script that was given and it should work.
Great tutorial, it’s helped me a lot.