To install your new 1/4" Jaws on your Cam-Lock Vise you will need your depth key and you will need to move your vise lever to the upright, unlocked position. Your tension adjust should be at the lowest setting possible.
REMOVING JAWS: Pinch the Jaws together with two fingers and use a single pin of the depth key to push the pins holding the vice jaw out the front of the sharpener. Now remove these pins and set them aside and then remove the Jaws. Be sure to keep them pinched together as there's a spring inside that can easily be lost.
INSTALLING JAWS: Take your new Jaws and slide them into the vacant spot in the Vise and reinsert the pins. They can be reinserted through the front of the back of the vise. You will need to line the pins up with the hole through the jaw and the polyurethane spring, which can take some fiddling until it slides in easily.