Best way to set Screen-capture shortcut button in to Xbox Controller

[CodeNamed1]

Hi,

 

So I want to set my XBOX button to be my screen shot button shortcut. I can't find a good way of doing this and a way to it to be on my controller and not in to my keyboard. I don't want to use the XBOX windows software screen-capture function into this, cause it does this weird flash thing on the screen which messes the picture to be kinda dark. The steam screen capture function would be better in this in my opinion but I don't know how to set it to be on my controller.. I know where to change it but it dose not respond to my controller.

 

SO help would be valued???

And yes I use XBOX controller on the PC and I specially wanna play Fallout 4 modded in doing this. Controller is in my opinion better when playing Fallout