What is a fume cupboard? When will it be used?

Modern fume cupboards, in real laboratories, come equipped with gas (for the bunsen burner), water, air, vacuum, and electrical outlets.
When working with chemicals, like HCL(Hydrochloric acid), which can give off toxic fumes and can burn skin and is corrosive to body tissue. Using the fume cupboard can suck away the toxic fumes that would otherwise kill you.