how to build a distributor of Nissan Tsuru III

Hello everyone, I hope you can help me, they asked me to arm a distributor from Nissan Tsuru III Mod 99 and it turns out that I am very confused with the disc the optical system since it has slots that correspond to each cylinder but there is a small square that is in different position according to it, the guide coincides the same if you put the disc with a face up or that face you put it down.
I thank you if there is someone who can help me to place the album correctly.
THANK YOU SO MUCH.
My email is
Or here in the forum, thanks again.

First put the engine tuning.
Cylinder One upper dead point, the smallest notch indicates the cylinder one is there the correct position of the synchronia disc of the Optical Sensor.