The best way to describe kinetic and potential energy is a roller coaster example. As the roller coaster is going up the hill it has stored energy (potential energy) in the possibility of the roller coaster going backwards. It also has stored up potential energy when the coaster goes over the top of the hill and is ready to fall.
Kinetic energy is the actual energy of motion when the roller coaster actually starts to fall.
Another good example is a rubberband.
When you pull the rubberband back it has stored up potential energy to be fired.
When the rubberband is actually fired is kinetic energy.