Hi just wondering if anyone could help as I’m pulling my hair out don’t have much hair as it is

anyway I changed my dual mass flywheel with a solid one including the clutch and all that needed to be changed to convert it but now the car won’t start was told could be the crank case sensor which I’ve brought a new one and changed again no start tried easy start will go but over rev and then cut back off and again no start now been told it’s the incorrect fly wheel as the new one has teeth but the old one is like square holes on a plate so would that make any difference or am I missing something I’ve checked and double checked the wires etc and nothing is missing?