Weld player or npc on to animation rig

I already know how to weld but the problem iays when i weld like player or npc to animation rig it just stay in one place not moving with the rig animation. Here’s the example

Yeah i just the part that welded to the rig move along with the part that it welded to while the animation is playing. Hope you guys can help me :sunglasses: :sunglasses: :sunglasses: