The yellow cables may be for ethernet. They have a modular plug, usually transparent plastic and a bit larger than the RJ11 plugs that go into the rear of telephones etc.
You will need a network interface on your PC. Most modern motherboards come equipped with anj integral one, so check that you have or do not have, on the rear of your PC, a socket that will accept the yellow cable plugs.
If you don't find a suitable socket, let us know and we will reccomend some suitable PCI netwrok card (they are very cheap).