Here are some great videos that show how to build your own sluice box and high banker.
Do It Yourself Gold Sluice Box
Build a High Banker
FEEDING THE SLUICE
Feed your gold-bearing gravel into the upper portion of the sluice box in carefully regulated amounts. Do not, under any circumstances, dump a large amount of gravel into the sluice box all at once! The gravel must be fed at a pace that will not overload the riffles. How can you tell when the riffles are overloading? It is simple. If you cannot see the uppermost “crest” of each riffle bar at all times, you are feeding the gravel too fast. Back off a bit. The use of a 1/4 inch classifier screen to pre-screen material before dumping into the sluice box can save much time and effort. The penalty for overloading your riffles often resullts in lost gold! Each time a new load of gravel is dumped into a sluice box with overloaded riffles, any gold in that gravel will wash right over the material that is clogging your riffles and out the discharge end of the box.