When an inclined plane, a type of simple machine, is wrapped around a cylinder, it forms a screw, which is another type of simple machine. Machines are mechanisms that can make work easier to do.
Work is a product of the amount of force applied times the distance traveled in performing a task. A machine does not decrease the work that needs to be done but changes the way that force is applied in completing the work.
An inclined plane is simple machine with a sloped surface that can be used to move an object from one height to another by pushing it up the slope. Using an inclined plane decreases the amount of force that must be exerted per unit distance but increases the distance over which it must be applied, providing an easier way to move the object than by lifting it directly.
If a long, narrow inclined plane was wound around a central column, much like a spiral staircase, the result would be a screw. That screw could then employ the same methods as its straight predecessor in order to make work easier.