Remove the terminals of the battery and take off the distributor cap. If your automobile does not contain a distributor, then turn the cam sensor position to the “Top Dead Centre”. Read the instructions from the user manual on how to achieve this in your car.
Turn the engine such that the crankshaft pulley is aligned with the timing belt at the 'O' position on the belt. Keep rotating the engine till the distributor rotor is in line with the markings on the distributor housing assembly.
Unscrew all the bots with the help of a spanner or a wrench that come in the way of the removal of the timing belt. This differs from car to car, in some vehicles hardly one or two bolt needs to be opened while in some other it is a quite complex procedure.
Loosen the timing belt tension controller and unscrew its bolts but do not remove them completely. Move the tension controller slightly far from the timing belt and now tighten those bolts again. Now the timing belt can be removed from the engine; carefully slide the belt off the engine.
Fit in the new timing belt in the space and follow all the steps in the reverse order. Read the car manual and tighten the timing belt accordingly. Carefully screw all the bolts and fire in the ignition to check if the time belt has perfectly settled or not.