How can natural gas be used for cars?
The same way petrol is for cars.
in a petrol car the piston pressurizes the fuel and then puts a spark in the chamber and then it explodes.
so the same way in place of petrol you can use natural gas ( with a slight modification the the car ). If you have access to YouTube here is a video on a natural gas being made from water
the same way the petrol explodes the gas can also explode.
hope this helps.