How does supply and demand effect on the goods?

Supply and demand intersect at an equilibrium point which determines the optimal quantity of whatever good and its price level. When the demand goes up, the price level increases and the quantity of goods increases as well. When the supply goes up, the price level goes down and the quantity of the good increases. It is easier to visualize this relationship by drawing the graph with a downward sloping demand curve intersecting an upward sloping supply curve.

(When drawn, it should resemble the letter "X")