I have 1990
Mercedes 560 SEL. I recently replaced the hydraulic suspension pump. I took off the distributor so that it would be easier to get access to the bolts. I was careful not to move the distributor rotor, but I must have moved it because now I can't get the car to start. So I then aligned the pointer on the timing chain cover to TDC mark on the vibration damper (the big zero right ???) I aligned the rotor to the notch on the distributor housing. still won't start

I aligned the pointer to the TDC mark by using the ignition switch to turn the motor. The pointer wasn't exactly on the TDC mark, but it was pretty darn close. How can I turn the engine manually so that I can align it exactly? I read that I should turn the crankshaft bolt. Where is that? Can the rotor be the issue? The
car started like new until now.
Thanks and Merry X-mas