Surface area is the sum of the area of all sides of the figure. In other words, it is the area of the outside surface of the figure.
Volume is the amount of area inside the figure.
To calculate surface area, I first find the area of all of the surfaces. A cube has 6 surfaces that are all the same size. Those surfaces are squares. Since there are six of those squares in a cube, I multiply the area of one side by 6. Now I have the surface area of the cube.