I began by collecting the materials I wanted in my tank. Rock, wood, twigs, laterite, sand, and gravel. I used these to "sketch" out a rough design and for brainstorming an overall look and functional layout within the tank.
With the design in front of me I cut a piece of mat board to fit the back of the aquarium and applied a warm, yellowish brown gradient of acrylic paint that closely matched some of the colors in the gravel, rock and wood. This will be the backdrop for the tank and was inspired by photos I looked at while researching the Rio Negro. I am considering making this a "black water" tank by using gardening peat in the filter to stain the water a brownish color.
Next I emptied the tank and placed it on the stand before checking for level.
I then used masking tape to mark where I wanted the major features of the tank to go.
After attaching the background I went to work on the substrate by mixing laterite and sand together while being sure to keep it's highest point towards the back corner of the tank below the bottom layer of masking tape.
Next I stacked my rocks to create something akin to a riverbank setting.
Next came the wood and twigs that I was hoping would simulate roots. This wood has not been saturated with water and has a tendency to float so I used the twigs to wedge it into place.
I then removed the tape and sprinkled a layer of river gravel across the rocks and laterite to give a natural and slightly more uniform appearance to the entire tank.