If you want a true amazon biotope tank then the tank will have no plants at all, the blackwater streams of the amazon basin are so acidic and dark coloured (hense the name "blackwater") that plant life cant exist, the only time the amazon is rich in plant life is during the wet season when the rivers flood into the jungle.
Give the tank a sand substrate, silver or playpit sand is very alike to the bottom of the amazon, and then decorate with large pieces of bogwood and smooth flat pebbles or pieces of thick slate. To give the tank its final finishing touches use some peat in the filter to stain the water a tannin rich tea colour.
Supply a good flow from a internal filter or powerhead placed at one end of the tank though be careful not to use one that is too powerful or you will create a whirlpool effect.
The fish you stock all depend on the size of the tank but whatever the size there is a amazon community to fit. A typical amazon biotope would have cichlids, characins and catfishes but there are many oddballs that could work too.