1990 Oldsmobile Cutlass How to set the timing

1990 Olds Cutlass Supreme mileage: 165,000. I recently replaced the timing chain. After getting all the gears and the chain in place, I started the car to make sure it was timed correctly; it ran like a true champ. The problem is that I didn’t have the crank pulley on while running the car so the keyway flew out and the crank kept spinning while the camshafts came to a stop. How do I line everything back up to get it back in time? And do I have serious problems if the crankshaft will spin only one rotation either way? Valve damage? Please help!