Rotary Encoder Application

How can i implement a rotary encoder in application with the MAG ALPHA sensor family?

That is quite an open-ended question! One of the advantages of the MagAlpha is the mechanical / magnetic versatility that it allows these types of designs. I will illustrate a very common, basic approach to a motor encoder solution, but keep in mind that we can change this in a myriad of ways to suit specific design requirements (e.g. move sensor to side-shaft, change magnet to ring, add multiple poles to magnet, change orientation of MagAlpha to the magnet, etc…)