You can run lengths of cable out to locations that you need. You can also connect a switch or an access point to the end of that cable to offer multiple connection jacks or add wireless capabilities to that location. Keep in mind that the cable does have a point at which the signal will break down if you go too far.
I would recommend using Solid Cable CAT5E (like
this cable). CAT5E is rated to cover distances up to 350 meters before the signal degrades. Get Solid Cable rather than UTP (Unshielded Twister Pair) or Stranded. Solid Cable has larger gauge wires and the wires are insulated, thus these cables are better suited to cover longer distances with fewer problems.
At a minimum, you would want to bury the cables 8" down or more. You might consider running it through some buried conduit so that the wires would be better protected from being damaged.