1. Sew up the side and shoulder seams of the doll/stuffed animal leaving a small hole in the top of the side seam. This hole should be the same size as the shank of the joint. The joint has two round disks, one with a screw attached. Insert this screw into the hole in the side seam. If it fits loosely, remove it and sew the seam slightly longer so that the screw fits snugly in the hole. Remove it from the doll.
2. Sew up the arm, leaving an opening large enough to easily fit the whole screw side of the joint through. Make a hole on the inside of the arm at the shoulder. This hole should be the same size as the hole in the side seam. Stick the screw through this hole from the inside of the arm.
3. Stick the screw into the hole in the side seam to attach the arm to the body. Reach inside the body and place the other side of the joint on the screw.
4. Place the lock washer on the screw with the flat side toward the joint. Be sure that you have the joint in the correct position as it is very hard to remove the lock washer once it is in place. Press the lock and the joint together firmly. You may use the opening in the top of a glass soft drink bottle as a tool to press it firmly into place.
5. Attach the other arm. Stuff the arms and slipstitch the opening closed. If adding legs, attach them in the same way before you stuff the body and sew it closed.