its in the name! a consumer is an animal/thing that CONSUMES/EATS things like producers. there's different tiers to the food web. the basic food web is Primary Producers (such as plants, like trees, Grass, dandelions), Primary consumers (Certain bugs like caterpillars, some mammals like squirrels), secondary consumers (small birds, snakes, etc. they eat they primary consumers!), and tertiary consumers (foxes, lions, hyenas, big preditors who eat other consumers.)
a fox (tertiary) would eat a rabbit (primary consumer)
a beetle (primary consumers) would eat plants/grasses (producers), to which a mantis (secondary) would eat the beetle, to which a frog would eat the mantis (tertiary, though if you kept going higher and higher it would go down, but just for an immediate example :) )
hope thats a bit helpful, sorry if it's a bit messy!