Hey guys,
I dont think I understand this pedal yet, I have the following effects:

Guitar -> TU3 -> KH95-> TS9 -> Amp Input

Amp FX Loop Send -> DD3 -> PS6 -> AF2(flanger) -> Amp FX loop return

know I dont know were to put the NS2 in all this, in the fx loop or in front of the amp and how all the four connections work.

Please Help
Well, I honestly never put mine in the FX loop, so I don't know if it works there or not, someone else will have to answer that part. When put in front of the amp, just put it as close to the amp as possible. That will ensure that it is reducing the noise created by as many of the pedals as possible. I put mine after every pedal I have, except my looper. I want the looper to get as clean of a signal as it can, so it records without the noise of the pedals. In your setup, after the OD and before the amp. You can try it in the FX loop as well. It wont hurt it. Just put it after all the pedals (after the AF2), and right before the return input.