Pressure sensor AMS5915 I2CS code

Hello,
I am completely new to this, very little electronics and arduino experience.
What I am trying to eventually do is use an Arduino UNO to read a pressure and ultimately turn on or off a vacuum pump based on that pressure reading.
My first problem is connecting and using the pressure sensor. I have found some bits and pieces of code to convert the voltage reading into pressure, but the pressure values I receive seem way off and it seems to still read pressures even when the sensor is disconnected.
So, my questions are how exactly should I connect the pressure sensor and what is the arduino code I need to display the correct pressure reading in the serial monitor (converting the voltage reading to pressure reading)?

I have the AMS 5915 I2CS pressure sensor, data sheet is attached.
I have a 12V vacuum pump from sparkfun
I am using an Arduino UNO

ams5915_data_sheet.pdf (246 KB)

Not familiar with that sensor, but check these links. https://www.google.com/search?ie=UTF-8&oe=UTF-8&q=ams5915&domains=http%3A%2F%2Fforum.arduino.cc&sitesearch=http%3A%2F%2Fforum.arduino.cc