1st gear: use when speeds are low such as below 10 mph- e.g. it should be used for moving off.
2nd gear: use when speeds reach between 10 to 15 mph.
3rd gear: use when speeds reach between 15 to 20 mph.
4th gear: use when speeds reach between 35 to 40mph.
5th gear: use when speeds are high such as above 45 mph, this is also known as the ‘cruising speed’- e.g. usually used on dual carriageways and motorways.
The purpose of the clutch is to disengage the engine from the wheels, but you would best know its purpose when driving to change the gears in order to alter the speed of the car. In order to use the clutch to change the gears press the clutch down to the floor, then with your left hand change into the gear you want to go into using the gear stick.