autotrophs, heterotrophs, and decomposers, how do they interact together??

Answer 1

Its basically a web. Autotrophs (producers) are usually plants and synthesize their food with the help of sunlight. Heterotrophs are the organisms that feed on these plants(herbivores), or on the animals that are feeding on these plants(carnivores). these are collectively called as consumers. when all these producers and consumers die, the organic matter in their bodies are fed upon and thus broken down by decomposers. these thus release complex matter to simple forms which are again ready to be taken up by the plants. the cycle continues.

Answer 2

Autotrophs make the food for themselves.
Heterotrophs eat autotrophs or other heterotrophs. Decomposers break down dead autotrophs and heterotrophs as well as the wastes from those.
The nutrients released from this dead organic matter or waste is available for the autotrophs to take up and put back into the cycle.