Besides using producers for energy itself, what do producers do with energy storage molecules?

Producers, or autotrophs, make their own organic molecules. Consumers, or heterotrophs, get organic molecules by eating other organisms.
A food chain is a linear sequence of organisms through which nutrients and energy pass as one organism eats another.
In a food chain, each organism occupies a different trophic level, defined by how many energy transfers separate it from the basic input of the chain.