How to start with ACS712-30A current sensor.

I m using acs712 30A first time and not able to understand its functionality and how its work.
I want to measure AC Current and Voltage. I m using Arduino UNO board with it.

http://wiring.org.co/learning/basics/currentacs712.html

There is not much to it.

I suggest that you simply wire up a 150 W tungsten bulb to it - very carefully - to check it out.