You can purchase books on this subject from this place:

http://elevator-world.com/

Well if you explained to us what you do understand or more importantly what baffles you then we might be able to help you. Learning anything requires effort by the student. Show us some effort and people here will help you. Show us only desires...

Do you know the difference between a hydraulic elevator and a traction elevator?

"Relay logic elevator

Although relay logic has been replaced by modern electronic devices, it's still now used on old elevators.The image below shows a basic relay logic (designed for educational purpose) of a traction elevator with manual doors.Basically an elevator panel consists of a power circuit, which supplies the motor, and a low voltage control circuit: this one supplies the relay coils, the motor brake and the doors locking mechanism.At the head of the control circuit there are the safety switches.The automatic switch cuts off the relay circuit if an insulation failure occurs (for example between the doors safety circuit and the ground); that would be dangerous because the elevator may move with open doors.The interlock allows the requests when the door isclosed. However the motion of the elevator is allowed by a second switch, when the door is locked.The finals work if the elevator goes over an extreme floor (due to a motor brake failure, for example).The car safety brake is a mechanical device that prevents the elevator from falling; it works in combination with the governor.

SCHEMATIC (link)

https://sites.google.com/site/plcandcircuitdiagram/relay-logic-elevator