How do i fix my 1.4 petrol opel corsa utility 2003?

Car doesnt want to start. Engine turns, but no firing power. Replaced coil & plugs, aswell as jumping it, nothing happened.
Only thing Im think it might be is the crankshaft sensor.
How do I replace the crankshaft sensor on 1.4 opel corsa utility 2003 and where is it located