It is easy, just do a search at this site.
FYI, here is something that I posted some time ago relative to bears and electric fences.
ELECTRIC BEAR FENCE FOR BEE YARDS
I live in bear country and before I got my first colony I built my bear fence. It consists of three 16'X4' cattle panels, one cut in half to make a 8'X16' yard. Four corners consist of heavy steel pipe with fiber optics conduit slid over as an insulator. The cattle panels are secured to the insulation and off the ground. The panels are wired together with bare copper wire and soldered. This is the "hot" side.
I use a Paramak brand Magnum 12 volt solar fence charger which is expensive but of reliable quality to charge the system. (Shop for best $)
CO is very arid so I put an 18" wide "skirt" of sheet metal on the ground 6" outside the cattle panels & spiked to the ground. Chicken wire as suggested above would work. The fence charger is grounded to an 8' copper clad ground rod & all of the "skirt" is bare copper wired/soldered together & tied to the ground rod. System has been tested by the bears & it works well. Look at http://www.kencove.com/fence/76_Bear+Fence_resource.php
for info. Good luck & be safe.