A:Answer Rick, first part right.
Now you have two sets of three wires each coming from (and permanently attached to) the device; one set for each computer. On each of the two computers: plug the USB cables into ANY two USB ports. That takes care of the mouse and KB. Now look at the big plug at the end of the of the third cable which is video/monitor. Find a port/jack which is a mirror image as far as holes and pins. Examine it to make sure everything lines up. Gently try to plug it in just to be sure. If it fits, it will work. Tighten the screws and you're done.
You may find two potential problems, especially with older computers or laptops. The port may have more holes than the plug has pins. That should still work and shouldn't be a problem. The opposite IS A PROBLEM, don't force the plug in. If the latter is the case there are all kinds of adapters you can buy to solve that problem. The other things is the port on the computer may not have the screw-in configuration. This is not a problem, everything will still work, but it is a real nusiance. I had a situation like that once and there was no good solution. I just put everything where it would be disturbed and every once in a while the plug would fall out and I had to plug it back in .