2D Positioning Localization
Question: How in the world do I approach this, I'm a beginner when it
  comes to sensor fusion, sensors in general and most of robotics.


You approach this with a kalman filter. The kalman filter keeps track of the state of the system. To do this it is best to have a knowledge of signal processing\theory as you will need to come up with a model of the system states. There are many resources to enable you to do this. To explain how a kalman filter works is beyond the scope of this fourm as a few weeks could be spent on learning how they work.