Part to bone welding

So im makin a custom avatar remodel of mine and im trying to weld a part to a bone to that i can then have a part that moves with the bone that moves other parts such as the arms & head with the rib bone and a part that moves with the hip bone that moves the legs with it. However i cannot figure out how to do so since a tried doing rigid constraints but that didn’t work as it didn’t move the part with the bone.



(ps: as an additional question since i still dont have access to the bug reports is that some of my plugins only work if i run Test [pressing F8])