Choose a part of the creek that has a steady flow of water in which to put your box. Clear a space in the creek and place your box in the gap. Put the top facing upstream so that the water flows through the box. The riffles will then be at the downstream end. Prop up the top of your one metre-long box so that it is about ten centimeters higher than the bottom. That’s about a handbreadth.
Ideally, you should have about a couple of centimeters of water flowing through. Put a generous shovel full of gravel in the top end. If the water sweeps the bigger gravel and grit away down the box and leaves a small beach in front of the first riffle, your flow is just right. If it washes every bit of grit out of the box and the riffles start to float off, it is too fast. If nothing much moves, even after using your rake to help the big stones through, it is too slow.
When you have the flow just right, check the downstream end to make sure there is room to receive the tailings that will be coming out of the box. They pile up quickly and interfere with the flow of water. During sluicing, a few sweeps with the rake or your gumboot will keep the tailings clear of the end. You are now set to dig for gold.
Don’t be surprised if you see some gold in your box after the first few bucketfuls—fine gold and small flakes don’t always go down to rock bottom.